Relevant bibliographies by topics / Wave blocking

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Wave blocking'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Wave blocking"

1

CHRISTENSEN, C. WIIN, and A. WIIN-NIELSEN. "Blocking as a wave-wave interaction." Tellus A 48, no. 2 (March 1996): 254–71. http://dx.doi.org/10.1034/j.1600-0870.1996.t01-1-00005.x.

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2

Christensen, C. Wün, and A. Wiin-Nielsen. "Blocking as a wave—wave interaction." Tellus A: Dynamic Meteorology and Oceanography 48, no. 2 (January 1996): 254–71. http://dx.doi.org/10.3402/tellusa.v48i2.12059.

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Yang, Xiaoye, Gang Zeng, Guwei Zhang, Jingwei Li, Zhongxian Li, and Zhixin Hao. "Interdecadal Variations of Different Types of Summer Heat Waves in Northeast China Associated with AMO and PDO." Journal of Climate 34, no. 19 (October 2021): 7783–97. http://dx.doi.org/10.1175/jcli-d-20-0939.1.

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AbstractThe summer heat waves (HWs) in Northeast China (NEC) during 1961–2016 can be classified into two types, namely, wave train HWs and blocking HWs based on the hierarchical clustering algorithm by using ERA-Interim daily datasets. Wave train HWs occurred accompanied by eastward-moving wave trains with a “− + − +” structure formed over Eurasia, while the blocking HWs occurred with blocking circulation anomalies over Eurasia. In general, the blocking HWs could cause the positive temperature anomalies in NEC to last longer than wave train HWs. During the period from 1961 to 2016, the wave train HWs experienced an interdecadal variation from less to more, while the blocking HWs experienced interdecadal variations of less–more–less. Regression analysis and information flow indicate that the interdecadal variation of the wave train HWs is associated with Atlantic multidecadal oscillation (AMO) and Pacific decadal oscillation (PDO), while the interdecadal variation of the blocking HWs is more likely associated with PDO. The positive phase of AMO (negative phase of PDO) could increase the wave train (blocking) HWs by strengthening the zonal wave train similar to the Silk Road pattern (the arched wave train like the polar–Eurasian pattern). The observed results are in agreement with the numerical experiments with the NCAR Community Atmosphere Model, version 5.3.
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Moreira, R. M., and D. H. Peregrine. "Nonlinear interactions between deep-water waves and currents." Journal of Fluid Mechanics 691 (December 6, 2011): 1–25. http://dx.doi.org/10.1017/jfm.2011.436.

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AbstractThe effects of nonlinearity on a train of linear water waves in deep water interacting with underlying currents are investigated numerically via a boundary-integral method. The current is assumed to be two-dimensional and stationary, being induced by a distribution of singularities located beneath the free surface, which impose sharp and gentle surface velocity gradients. For ‘slowly’ varying currents, the fully nonlinear results confirm that opposing currents induce wave steepening and breaking within the region where a high convergence of rays occurs. For ‘rapidly’ varying currents, wave blocking and breaking are more prominent. In this case reflection was observed when sufficiently strong adverse currents are imposed, confirming that at least part of the wave energy that builds up within the caustic can be released in the form of partial reflection and wave breaking. For bichromatic waves, the fully nonlinear results show that partial wave blocking occurs at the individual wave components in the wave groups and that waves become almost monochromatic upstream of the blocking region.
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Yang, Guoliang, Shuai Feng, and Wenjia Huang. "Wave-Blocking Characteristics of Corrugated Plates under Explosion." Shock and Vibration 2020 (February 29, 2020): 1–8. http://dx.doi.org/10.1155/2020/5895812.

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Corrugated-board explosion-proof wall is the main means to prevent explosion shock wave damage, and it is important to study the effect of different corrugated plates on the shock wave. Using a high-speed schlieren experimental system and an air overpressure test system, the wave-blocking characteristics of different forms of corrugated plates are comprehensively studied. The schlieren images were used to analyze the influence that the corrugation shape of a corrugated plate has on the shock wave propagation characteristics. The results show that the reflection process of the triangular-, trapezoidal-, and half-cylindrical-shaped corrugated plates exhibit differences. The number of reflected waves from the triangular corrugated plate is much greater than that from the other corrugated plates, and it will consume more energy. The diffraction wave-front velocity has a trend of initially decreasing and then increasing and is also reduced by different degrees by the reflection. Comparative analysis of the schlieren images and the air shock wave overpressure test shows that plates corrugated with different corrugation shapes decrease the diffraction overpressure peak and exhibit a hysteresis.
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Luo, Dehai, and Wenqi Zhang. "A Nonlinear Multiscale Theory of Atmospheric Blocking: Eastward and Upward Propagation and Energy Dispersion of Tropospheric Blocking Wave Packets." Journal of the Atmospheric Sciences 77, no. 12 (December 2020): 4025–49. http://dx.doi.org/10.1175/jas-d-20-0153.1.

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AbstractIn this paper, a nonlinear multiscale interaction model is used to examine how the planetary waves associated with eddy-driven blocking wave packets propagate through the troposphere in vertically varying weak baroclinic basic westerly winds (BWWs). Using this model, a new one-dimensional finite-amplitude local wave activity flux (WAF) is formulated, which consists of linear WAF related to linear group velocity and local eddy-induced WAF related to the modulus amplitude of blocking envelope amplitude and its zonal nonuniform phase. It is found that the local eddy-induced WAF reduces the divergence (convergence) of linear WAF in the blocking upstream (downstream) side to favor blocking during the blocking growth phase. But during the blocking decay phase, enhanced WAF convergence occurs in the blocking downstream region and in the upper troposphere when BWW is stronger in the upper troposphere than in the lower troposphere, which leads to enhanced upward-propagating tropospheric wave activity, though the linear WAF plays a major role. In contrast, the downward propagation of planetary waves may be seen in the troposphere for vertically decreased BWWs. These are not seen for a zonally uniform eddy forcing. A perturbed inverse scattering transform method is used to solve the blocking envelope amplitude equation. It is found that the finite-amplitude WAF represents a modified group velocity related to the variations of blocking soliton amplitude and zonal wavenumber caused by local eddy forcing. Using this amplitude equation solution, it is revealed that, under local eddy forcing, the blocking wave packet tends to be nearly nondispersive during its growth phase but strongly dispersive during the decay phase for vertically increased BWWs, leading to strong eastward and upward propagation of planetary waves in the downstream troposphere.
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Moreira, R. M., and J. T. A. Chacaltana. "Vorticity effects on nonlinear wave–current interactions in deep water." Journal of Fluid Mechanics 778 (July 31, 2015): 314–34. http://dx.doi.org/10.1017/jfm.2015.385.

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The effects of uniform vorticity on a train of ‘gentle’ and ‘steep’ deep-water waves interacting with underlying flows are investigated through a fully nonlinear boundary integral method. It is shown that wave blocking and breaking can be more prominent depending on the magnitude and direction of the shear flow. Reflection continues to occur when sufficiently strong adverse currents are imposed on ‘gentle’ deep-water waves, though now affected by vorticity. For increasingly positive values of vorticity, the induced shear flow reduces the speed of right-going progressive waves, introducing significant changes to the free-surface profile until waves are completely blocked by the underlying current. A plunging breaker is formed at the blocking point when ‘steep’ deep-water waves interact with strong adverse currents. Conversely negative vorticities augment the speed of right-going progressive waves, with wave breaking being detected for strong opposing currents. The time of breaking is sensitive to the vorticity’s sign and magnitude, with wave breaking occurring later for negative values of vorticity. Stopping velocities according to nonlinear wave theory proved to be sufficient to cause wave blocking and breaking.
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Wen, Hua Bing, Lin Bo Liu, Zi Long Peng, and Qi Dong Zhong. "Research on the Effects of Blocking Mass on Vibration Resistance Performance of L-Shaped Plates." Applied Mechanics and Materials 482 (December 2013): 131–35. http://dx.doi.org/10.4028/www.scientific.net/amm.482.131.

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The theory of vibration resistance of blocking mass at the corner interface of L-shaped plates is put forward from the perspective of wave approach. The equation of transmission and reflection coefficients of flexure wave is deduced by the presented theory. Based on FE/SEA method, the vibration resistance performance of the hollow blocking mass at the corner interface of L-shaped plates was studied through numerical simulation. The results show that the hollow blocking mass can impede the propagation of the high frequency vibration waves, reduce the vibration and sound radiation of the latter plate, and increase the influence of the reflection waves on the former plate. However, the overall radiant energy is basically identical to the L-shaped plates without the hollow blocking mass.
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Xu, Ying, Wuyin Jin, and Jun Ma. "Emergence and robustness of target waves in a neuronal network." International Journal of Modern Physics B 29, no. 23 (September 17, 2015): 1550164. http://dx.doi.org/10.1142/s0217979215501647.

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Target waves in excitable media such as neuronal network can regulate the spatial distribution and orderliness as a continuous pacemaker. Three different schemes are used to develop stable target wave in the network, and the potential mechanism for emergence of target waves in the excitable media is investigated. For example, a local pacing driven by external periodical forcing can generate stable target wave in the excitable media, furthermore, heterogeneity and local feedback under self-feedback coupling are also effective to generate continuous target wave as well. To discern the difference of these target waves, a statistical synchronization factor is defined by using mean field theory and artificial defects are introduced into the network to block the target wave, thus the robustness of these target waves could be detected. However, these target waves developed from the above mentioned schemes show different robustness to the blocking from artificial defects. A regular network of Hindmarsh–Rose neurons is designed in a two-dimensional square array, target waves are induced by using three different ways, and then some artificial defects, which are associated with anatomical defects, are set in the network to detect the effect of defects blocking on the travelling waves. It confirms that the robustness of target waves to defects blocking depends on the intrinsic properties (ways to generate target wave) of target waves.
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Berrisford, P., B. J. Hoskins, and E. Tyrlis. "Blocking and Rossby Wave Breaking on the Dynamical Tropopause in the Southern Hemisphere." Journal of the Atmospheric Sciences 64, no. 8 (August 2007): 2881–98. http://dx.doi.org/10.1175/jas3984.1.

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Rossby wave breaking on the dynamical tropopause in the Southern Hemisphere (the −2-PVU surface) is investigated using the ERA-40 dataset. The indication of wave breaking is based on reversal in the meridional gradient of potential temperature, and persistent large-scale wave breaking is taken as a strong indication that blocking may be present. Blocking in the midlatitudes is found to occur predominantly during wintertime in the Pacific and is most vigorous in the east Pacific, while during summertime, the frequency of blocking weakens and its extent becomes confined to the west Pacific. The interannual variability of blocking is found to be high. Wave breaking occurs most frequently on the poleward side of the polar jet and has some, but not all, of the signatures of blocking, so it is referred to as high-latitude blocking. In general, cyclonic wave breaking occurs on the poleward side of the polar jet, otherwise anticyclonic breaking occurs. However, at least in wintertime, wave breaking in the New Zealand/west to mid-Pacific sector between the polar and subtropical jets is a mixture between cyclonic and anticyclonic types. Together, episodes of wave breaking and enhanced westerly flow describe much of the variability in the seasonal Antarctic Oscillation (AnO) index and give a synoptic manifestation of it with a focus on the date line and Indian Ocean that is in agreement with the centers of action for the AnO. During summertime, anticyclonic wave breaking in the upper troposphere is also to be found near 30°S in both the Pacific and Atlantic, and appears to be associated with Rossby waves propagating into the subtropics from the New Zealand region.
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Dissertations / Theses on the topic "Wave blocking"

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Dowdall, James. "Wave Blocking Phenomena and Ecological Applications." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33155.

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The growing flow of people and goods around the globe has allowed new, non-native species to establish and spread in already fragile ecosystems. The introduction of invasive species can have a detrimental impact on the already established species. Thus, it is important that we understand the mechanisms that facilitate or prevent invasion. Since reaction-diffusion invasion models produce travelling waves we can study invasion by looking at the mechanisms that allow for wave propagation failure, or wave-blocking. In this thesis we consider a perturbed reaction-diffusion model in which the perturbation resides in either the reaction or diffusion term. In doing so we exploit the underlying symmetry of our problem to define a region in the appropriate parameter space that leads to wave blocking. As a demonstrative example we apply our theory to the bistable equation and consider the effects of various perturbations.
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Longley, Kaitlyn E. "WAVE CURRENT INTERACTIONS AND WAVE-BLOCKING PREDICTIONS USING NHWAVE MODEL." Monterey, California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/32857.

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Wave blocking in river inlets is examined using the NHWAVE (Non-Hydrostatic Wave) model under development. Blocking flows at river inlets are a significant hazard to navigation. Refractive and shoaling effects contribute to the enhancement of wave field energy, causing instabilities and breaking, resulting in energy dissipation and transfer at the blocking point. The non-linearity of wave-current interactions and wave breaking makes the dynamics of blocking flows difficult to model. Current efforts to use wave-averaged models are insufficient to describe the complex dynamics that occur within one or two wavelengths of a blocking point. NHWAVE uses the non-hydrostatic, incompressible Navier-Stokes equations to model fully dispersive wave processes in the time domain. Monochromatic wave cases are explored and compared with lab experiments of energy dissipation due to wave breaking under conditions of strong opposing current, conducted in 2002 at the University of Delaware by A. Chawla and T. J. Kirby. The model was initially unable to resolve the boundary conditions necessary to model wave blocking in a tank domain. However, developments to the numerical scheme in NHWAVE have advanced its capability in this regard. Due to the difficulties of modeling the dynamics of wave blocking and the boundary conditions in a wave tank, only preliminary results were obtained. NHWAVE needs further development; it shows promise, however, to be able to predict wave reflection, blocking, and dissipation on a strong opposing current.
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Lajoie, Guillaume. "Wave blocking phenomenon: A dynamical systems approach." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27468.

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Traveling waves are an intricate part of many physical phenomena such as electrical impulses in nervous tissue and cardiac muscle, many chemical reactions and the action potential in certain types of conductors. The problem of propagation failure of such waves due to various perturbations, also known as wave blocking, remains a relatively elusive concept that is nevertheless observed in experiments. Some model specific research has been conducted on the subject, most of which utilizes numerical tools. The object of this thesis is to adopt a symmetry based approach to obtain results that are much more general. We study the effect of a symmetry breaking perturbation acting on an ODE with translational symmetry, modeling a traveling wave. We show that for a large class of such systems, the wave blocking phenomenon can be explained by the presence of saddle-node bifurcations of solutions on a carefully chosen invariant curve. We achieve this by using symmetry reduction tools as well as properties of center manifolds.
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Masato, Giacomo. "A wave-breaking analysis of northern hemisphere winter blocking." Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.541946.

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Geldenhuis, Andre. "The Atmospheric Gravity Wave Transfer Function above Scott Base." Thesis, University of Canterbury. Physics and Astronomy, 2008. http://hdl.handle.net/10092/3698.

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Gravity waves have a significant dynamic effect in the mesosphere. In particular, they drive the mesospheric circulation and are the reason that the summer polar mesosphere is cooler than the winter polar mesosphere. This thesis examines whether the effects of gravity waves are largely determined by filtering effects which allow only gravity waves with certain properties to propagate into the atmosphere. The filtering of gravity waves above Scott Base, Antarctica is examined using a radiosonde derived gravity wave source function, an MF-radar derived mesospheric gravity wave climatology, and a model derived filtering function. Least squares fitting of the source function and filtering function to the observed mesospheric gravity wave climatology allows us to determine which gravity wave phase velocities and propagation direction are likely to be present in the mesosphere and the relative importance of filtering and sources in this region. It is concluded the blocking of eastward gravity waves is important in winter and westward waves in summer.
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Roy, Christian. "The Origin of Wave Blocking for a Bistable Reaction-Diffusion Equation : A General Approach." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22704.

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Mathematical models displaying travelling waves appear in a variety of domains. These waves are often faced with different kinds of perturbations. In some cases, these perturbations result in propagation failure, also known as wave-blocking. Wave-blocking has been studied in the case of several specific models, often with the help of numerical tools. In this thesis, we will display a technique that uses symmetry and a center manifold reduction to find a criterion which defines regions in parameter space where a wave will be blocked. We focus on waves with low velocity and small symmetry-breaking perturbations, which is where the blocking initiates; the organising center. The range of the tools used makes the technique easily generalizable to higher dimensions. In order to demonstrate this technique, we apply it to the bistable equation. This allows us to do calculations explicitly. As a result, we show that wave-blocking occurs inside a wedge originating from the organising center and derive an expression for this wedge to leading order. We verify our results with some numerical simulations.
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Marshall, Samuel David. "Sloping convection : an experimental investigation in a baroclinic annulus with topography." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:ca9cfaf5-49e8-4e30-b93a-65c27d1c8a15.

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This thesis documents a collection of experimental investigations in which a differentially-heated annulus was used to investigate the effects of topography on the atmospheric and oceanic circulation. To this end a number of experiments were devised, each using a different topographic base to study a different aspect of the impact of topography, motivated by the most notable outstanding questions found in a review of the literature, namely exploring the effects of topographic resonance, blocking via partial barriers, and azimuthally differential-heating via thermal topography. First of all, whilst employing sinusoidal wavenumber-3 topography to extend the experimental parameter space of a similar study, namely Read and Risch (2011), a new regime within a region of structural vacillation was encountered. Denoted as the ‘stationary-transition’ regime, it featured periodic oscillations between a dominant stationary wavenumber-3 flow and axisymmetric or chaotic flow. An investigation into topographic resonance followed, keeping the wavenumber-3 base, but with a sloped lid to add a beta effect to the annulus. This acted to increase the occurrence of stationary waves, along with the ‘stationary-transition’ regime, which was discovered to be a near-resonant region where nonlinear topographic resonant instability led to a 23 to 42 ‘day’ oscillatory structure. The base was then replaced with an isolated ridge, forming a partial barrier to study the difference between blocked and unblocked flow. The topography was found to impact the circulation at a level much higher than its own peak, causing a unique flow structure when the drifting flow and the topography interacted in the form of an ‘interference’ regime at low Taylor Numbers, as well as forming an erratic ‘irregular’ regime at higher Taylor Numbers. Lastly, this isolated ridge was replaced by flat heating elements covering the same azimuthal extent, in order to observe whether thermal topography could be comparable to mechanical topography. These azimuthally-varying heating experiments produced much the same results as the partial barriers study, despite the lack of a physical peak or bottom-trapped waves, suggesting that blocking is independent of these activities. Evidence of resonant wave-triads was noted in all experiments, though the component wavenumbers of the wave-triads and their impact on the flow was found to depend on the topography in question.
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Vautard, Robert. "Les echelles de temps de la circulation atmospherique : couplage interne et approches de la parametrisation des modes rapides." Paris 6, 1987. http://www.theses.fr/1987PA066657.

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Les interactions entre les modes lents et les modes rapides de la circulation atmospherique sont examinees a travers deux problemes. Le premier concerne le couplage entre les ondes de gravite et les ondes de rossby. En raison des erreurs d'observation, les modeles de prevision numerique engendrent des ondes de gravite rapides irrealistes. Ces modes doivent donc etre initialement filtres. Le probleme est aborde de maniere theorique par l'etude de l'existence et des proprietes d'une variete invariante de l'espace des phases, appelee "variete lente", qui est sensee contenir l'attracteur du systeme atmospherique. Nous montrons au moyen d'exemples et de theoremes mathematiques qu'une telle variete peut exister, mais que les algorithmes actuels ne convergent pas vers elle. Le deuxieme probleme concerne la generation de la variabilite basse-frequence de l'atmosphere. Nous montrons que la dynamique lente de grande echelle est largement gouvernee par le forcage qu'induisent les transitoires rapides de petite echelle. L'existence de plusieurs structures de grande echelle associees a des regimes de temps, maintenues par les ondes baroclines rapides venant se superposer, est demontree dans le cadre d'un modele quasi-geostrophique. L'alternance entre ces regimes contribue a l'essentiel de la variabilite basse-frequence aux latitudes temperees. Cette notion de "regime de temps", jusqu'ici definie de maniere vague, est abordee de facon quantitative et objective au moyen d'une methode variationnelle statistico-dynamique. Celle-ci permet la reconnaissance de plusieurs types de circulation persistante dont l'une constitue le phenomene de "blocage". Dans ce phenomene, nous montrons que les transitoires ont un effet positif et important pour le maintien de la structure de l'anomalie
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Ling, Alister R. "Blocking-like flows in a hemispherical barotropic model." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65945.

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Dionne, Pierre 1962. "Numerical simulation of blocking by the resonance of topographically forced waves." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65542.

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Books on the topic "Wave blocking"

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Tibaldi, Stefano, and Franco Molteni. Atmospheric Blocking in Observation and Models. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.611.

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The atmospheric circulation in the mid-latitudes of both hemispheres is usually dominated by westerly winds and by planetary-scale and shorter-scale synoptic waves, moving mostly from west to east. A remarkable and frequent exception to this “usual” behavior is atmospheric blocking. Blocking occurs when the usual zonal flow is hindered by the establishment of a large-amplitude, quasi-stationary, high-pressure meridional circulation structure which “blocks” the flow of the westerlies and the progression of the atmospheric waves and disturbances embedded in them. Such blocking structures can have lifetimes varying from a few days to several weeks in the most extreme cases. Their presence can strongly affect the weather of large portions of the mid-latitudes, leading to the establishment of anomalous meteorological conditions. These can take the form of strong precipitation episodes or persistent anticyclonic regimes, leading in turn to floods, extreme cold spells, heat waves, or short-lived droughts. Even air quality can be strongly influenced by the establishment of atmospheric blocking, with episodes of high concentrations of low-level ozone in summer and of particulate matter and other air pollutants in winter, particularly in highly populated urban areas.Atmospheric blocking has the tendency to occur more often in winter and in certain longitudinal quadrants, notably the Euro-Atlantic and the Pacific sectors of the Northern Hemisphere. In the Southern Hemisphere, blocking episodes are generally less frequent, and the longitudinal localization is less pronounced than in the Northern Hemisphere.Blocking has aroused the interest of atmospheric scientists since the middle of the last century, with the pioneering observational works of Berggren, Bolin, Rossby, and Rex, and has become the subject of innumerable observational and theoretical studies. The purpose of such studies was originally to find a commonly accepted structural and phenomenological definition of atmospheric blocking. The investigations went on to study blocking climatology in terms of the geographical distribution of its frequency of occurrence and the associated seasonal and inter-annual variability. Well into the second half of the 20th century, a large number of theoretical dynamic works on blocking formation and maintenance started appearing in the literature. Such theoretical studies explored a wide range of possible dynamic mechanisms, including large-amplitude planetary-scale wave dynamics, including Rossby wave breaking, multiple equilibria circulation regimes, large-scale forcing of anticyclones by synoptic-scale eddies, finite-amplitude non-linear instability theory, and influence of sea surface temperature anomalies, to name but a few. However, to date no unique theoretical model of atmospheric blocking has been formulated that can account for all of its observational characteristics.When numerical, global short- and medium-range weather predictions started being produced operationally, and with the establishment, in the late 1970s and early 1980s, of the European Centre for Medium-Range Weather Forecasts, it quickly became of relevance to assess the capability of numerical models to predict blocking with the correct space-time characteristics (e.g., location, time of onset, life span, and decay). Early studies showed that models had difficulties in correctly representing blocking as well as in connection with their large systematic (mean) errors.Despite enormous improvements in the ability of numerical models to represent atmospheric dynamics, blocking remains a challenge for global weather prediction and climate simulation models. Such modeling deficiencies have negative consequences not only for our ability to represent the observed climate but also for the possibility of producing high-quality seasonal-to-decadal predictions. For such predictions, representing the correct space-time statistics of blocking occurrence is, especially for certain geographical areas, extremely important.
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United States. National Aeronautics and Space Administration., ed. Blockage development in a transonic, axial compressor rotor. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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United States. National Aeronautics and Space Administration., ed. Blockage development in a transonic, axial compressor rotor. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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4

Center, Langley Research, ed. Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Center, Langley Research, ed. Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Center, Langley Research, ed. Wind-tunnel blockage and actuation systems test of a two-dimensional scramjet inlet unstart model at Mach 6. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Asai, H. Theoretical Study of THz Emission from HTS Cuprate. Edited by A. V. Narlikar. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780198738169.013.9.

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This article examines the THz emission from high-temperature superconducting (HTS) cuprates in the mesoscopic state using the intrinsic Josephson junction model. Cuprate superconductors are high-temperature superconductors that exhibit exotic electromagnetic properties. One of the remarkable features of HTS cuprates is high anisotropy due to their layered structures. Almost all HTS cuprates are composed of stacks of CuO2 layers and blocking layers which supply charge carriers to the CuO2 layers. The crystal structures of the HTS cuprates naturally form Josephson junctions known as intrinsic Josephson junctions (IJJs). This article first describes the basic theory of IJJ and the mechanism of THz emission before discussing the effect of temperature inhomogeneity on the emission properties. It then introduces a novel IJJ-based THz emitter that utilizes laser heating. Theoretical results show that the THz emission is caused by the strong excitation of transverse Josephson plasma waves in IJJs under a direct current bias.
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Benestad, Rasmus. Climate in the Barents Region. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.655.

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The Barents Sea is a region of the Arctic Ocean named after one of its first known explorers (1594–1597), Willem Barentsz from the Netherlands, although there are accounts of earlier explorations: the Norwegian seafarer Ottar rounded the northern tip of Europe and explored the Barents and White Seas between 870 and 890 ce, a journey followed by a number of Norsemen; Pomors hunted seals and walruses in the region; and Novgorodian merchants engaged in the fur trade. These seafarers were probably the first to accumulate knowledge about the nature of sea ice in the Barents region; however, scientific expeditions and the exploration of the climate of the region had to wait until the invention and employment of scientific instruments such as the thermometer and barometer. Most of the early exploration involved mapping the land and the sea ice and making geographical observations. There were also many unsuccessful attempts to use the Northeast Passage to reach the Bering Strait. The first scientific expeditions involved F. P. Litke (1821±1824), P. K. Pakhtusov (1834±1835), A. K. Tsivol’ka (1837±1839), and Henrik Mohn (1876–1878), who recorded oceanographic, ice, and meteorological conditions.The scientific study of the Barents region and its climate has been spearheaded by a number of campaigns. There were four generations of the International Polar Year (IPY): 1882–1883, 1932–1933, 1957–1958, and 2007–2008. A British polar campaign was launched in July 1945 with Antarctic operations administered by the Colonial Office, renamed as the Falkland Islands Dependencies Survey (FIDS); it included a scientific bureau by 1950. It was rebranded as the British Antarctic Survey (BAS) in 1962 (British Antarctic Survey History leaflet). While BAS had its initial emphasis on the Antarctic, it has also been involved in science projects in the Barents region. The most dedicated mission to the Arctic and the Barents region has been the Arctic Monitoring and Assessment Programme (AMAP), which has commissioned a series of reports on the Arctic climate: the Arctic Climate Impact Assessment (ACIA) report, the Snow Water Ice and Permafrost in the Arctic (SWIPA) report, and the Adaptive Actions in a Changing Arctic (AACA) report.The climate of the Barents Sea is strongly influenced by the warm waters from the Norwegian current bringing heat from the subtropical North Atlantic. The region is 10°C–15°C warmer than the average temperature on the same latitude, and a large part of the Barents Sea is open water even in winter. It is roughly bounded by the Svalbard archipelago, northern Fennoscandia, the Kanin Peninsula, Kolguyev Island, Novaya Zemlya, and Franz Josef Land, and is a shallow ocean basin which constrains physical processes such as currents and convection. To the west, the Greenland Sea forms a buffer region with some of the strongest temperature gradients on earth between Iceland and Greenland. The combination of a strong temperature gradient and westerlies influences air pressure, wind patterns, and storm tracks. The strong temperature contrast between sea ice and open water in the northern part sets the stage for polar lows, as well as heat and moisture exchange between ocean and atmosphere. Glaciers on the Arctic islands generate icebergs, which may drift in the Barents Sea subject to wind and ocean currents.The land encircling the Barents Sea includes regions with permafrost and tundra. Precipitation comes mainly from synoptic storms and weather fronts; it falls as snow in the winter and rain in the summer. The land area is snow-covered in winter, and rivers in the region drain the rainwater and meltwater into the Barents Sea. Pronounced natural variations in the seasonal weather statistics can be linked to variations in the polar jet stream and Rossby waves, which result in a clustering of storm activity, blocking high-pressure systems. The Barents region is subject to rapid climate change due to a “polar amplification,” and observations from Svalbard suggest that the past warming trend ranks among the strongest recorded on earth. The regional change is reinforced by a number of feedback effects, such as receding sea-ice cover and influx of mild moist air from the south.
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Book chapters on the topic "Wave blocking"

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Martin, Roland, Dimitri Komatitsch, Céline Blitz, and Nicolas Le Goff. "Simulation of Seismic Wave Propagation in an Asteroid Based upon an Unstructured MPI Spectral-Element Method: Blocking and Non-blocking Communication Strategies." In High Performance Computing for Computational Science - VECPAR 2008, 350–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-92859-1_32.

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Pires, Christian Willian Siqueira, Eduardo Charles Vasconcellos, and Esteban Walter Gonzalez Clua. "GPU Memory Access Optimization for 2D Electrical Wave Propagation Through Cardiac Tissue and Karma Model Using Time and Space Blocking." In Computational Science and Its Applications – ICCSA 2020, 376–90. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58799-4_28.

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Dyall, Kenneth G., and Knut Faegri. "Matrices and Wave Functions under Double-Group Symmetry." In Introduction to Relativistic Quantum Chemistry. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195140866.003.0016.

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Symmetry is one of the most versatile theoretical tools of physics and chemistry. It provides qualitative insight into the wave functions and properties of systems, and it has also been used successfully to obtain great savings in computational efforts. In the preceding chapter we examined time-reversal symmetry, and now we turn to the more familiar point-group symmetry. We show how relativity requires special consideration and extensions of the concepts developed for the nonrelativistic case, and how time-reversal symmetry and double-group symmetry are connected. Although the techniques that incorporate double-group symmetry presented here are primarily aimed at four-component calculations, they are equally applicable to two-component calculations in which the spin-dependent operators are included at the SCF stage of a calculation. In the preceding chapter, we have shown how the use of time-reversal symmetry can lead to considerable reduction in the number of unique matrix elements that appear in the operator expressions. However, we are also interested in the overall structure of the matrices of the operators. In particular, we are interested in possible block structures, where classes of matrix elements may be set to zero a priori. If the matrices can be cast in block diagonal form, we may save on storage as well as computational effort in solving eigenvalue problems, for example. Matrix blocking will already be effected by the point-group symmetry of the molecule.
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Llndzen, R. S. "Stationary Planetary Waves, Blocking, and Interannual Variability." In Advances in Geophysics, 251–73. Elsevier, 1986. http://dx.doi.org/10.1016/s0065-2687(08)60042-4.

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Macmaster, Neil. "Separate Worlds?: European Domination of the Chelif Plain." In War in the Mountains, 25–34. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198860211.003.0002.

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Between 1843 and the First World War European settlers occupied the richest, irrigated agricultural land of the Chelif plain from which the indigenous population was either driven back into the mountains or reduced to a proletarian, wage-labour status inhabiting the shanty towns. This chapter explores the remarkable dualism of colonial space, the contrast between the settler zone, and that of the surrounding mountains (Chapter 2). Europeans dominated the plain both economically and politically through the control of the municipal government of twenty townships, the communes de plein exercices (CPE) on which they held an automatic electoral majority. The colonial élite of wealthy landowners, rentiers, millers, bankers, lawyers, and industrialists protected the economic interests of the European community, while blocking state investment in development of the impoverished mountainous zones of the communes mixtes.
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Hafez, Yehia. "Blocking Systems Persist over North Hemisphere and Its Role in Extreme Hot Waves over Russia During Summer 2010." In Atmospheric Model Applications. InTech, 2012. http://dx.doi.org/10.5772/33810.

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Conference papers on the topic "Wave blocking"

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Suastika, I. K., M. P. C. de Jong, and J. A. Battjes. "Experimental Study of Wave Blocking." In 27th International Conference on Coastal Engineering (ICCE). Reston, VA: American Society of Civil Engineers, 2001. http://dx.doi.org/10.1061/40549(276)18.

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Peng, Bo, Ning Ma, and Xiechong Gu. "RANS Simulation on Wave Blocking and Breaking of Water Surface Waves Propagating on Current." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-23618.

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Wave-current interaction, a common phenomenon in the areas of estuary and gulf, is also notable in deep water sea area. When the current is strong enough, wave “blocking” accompanied by wave breaking takes place and leads to hazard sea conditions. On the other hand, wave countering current is also thought to be one of the main causes of occurrence of rogue waves in the ocean, which imperils offshore structures and is of much importance for research. Knowing this, viscous flow of wave generation on current is simulated by using Reynolds-Averaged-Navier-Stokes (RANS) equation for better understanding of its mechanism and flow field. In this study, two-dimensional waves propagating without current, along and against pre-existing large-scale current have been investigated. The validation of calculation has been demonstrated through comparing with preliminary experiments in Circulating Water Channel (CWC). When propagating in counter-current, wave is steepened and wave height increases dramatically, thus wave breaking occurs occasionally. Therefore, the variation of wave height and steepness with current velocity has been analyzed quantitatively. It has been confirmed that wave “blocking” occurs when current speed is comparable with group velocity of waves. And this is analyzed in detail in terms of kinematics, energy transfer and others. Accordingly, wave breaking is evaluated by the well-known classical wave breaking criterion. Furthermore, the proposed viscous model is compared with “simple bore dissipation model” to evaluate energy dissipation of wave breaking and improvement of numerical model for wave blocking is introduced. It has been shown that the present numerical model is applicable to reproduce the wave blocking and breaking phenomenon and it will be useful for future engineering purpose on predicting real sea conditions.
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RODRIGO, M., H. IKEDA, and M. MIMURA. "WAVE BLOCKING IN PARALLEL COUPLED NERVE FIBERS." In Third Asian Mathematical Conference 2000. WORLD SCIENTIFIC, 2002. http://dx.doi.org/10.1142/9789812777461_0043.

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Ris, R. C., and L. H. Holthuijsen. "Spectral Modelling of Current Induced Wave-Blocking." In 25th International Conference on Coastal Engineering. New York, NY: American Society of Civil Engineers, 1997. http://dx.doi.org/10.1061/9780784402429.097.

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Zhang, Zhiyang, Jingchao Bao, Yawen Fan, and Husheng Li. "Tracking via Blocking in Millimeter Wave Communication Networks." In 2018 IEEE International Conference on Communications (ICC 2018). IEEE, 2018. http://dx.doi.org/10.1109/icc.2018.8422674.

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Tiu, Johnny, and Richard Bachoo. "WAVE ANALYSIS OF A L-BEAM STRUCTURE WITH A BLOCKING MASS." In International Conference on Emerging Trends in Engineering & Technology (IConETech-2020). Faculty of Engineering, The University of the West Indies, St. Augustine, 2020. http://dx.doi.org/10.47412/ewgf2313.

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The wave vibration approach regards the vibrations present within a structure as waves, whereby each wave flows along a structural member and upon meeting a discontinuity; portions of the incident wave are reflected and transmitted across the discontinuity. The reflected, transmitted and propagating wave transformations are represented mathematically by matrices, which are used to develop a set of wave relation equations at each discontinuity that can be used to describe the frequency response of the system holistically. This method creates a systematic approach of analysing structures by utilizing common cases as building blocks for a specific structure. The L-joint, described as two beams meeting at right angles; is a ubiquitous case for spatial portal and structural frames, which may become geometrically complex. Such structures are well suited to a wave vibration approach due to the large number of geometric changes and the prevalence as well as recurrence of specific cases. In this paper, the L-joint expanded to include a blocking mass, typically employed in structural systems and allows for the isolation and reflection of vibration away from contiguous structural elements. Included are; variance of transmission and reflection matrix components as the size of the blocking mass increases, numerical examples and comparison to a Finite Element Model developed in ANSYS.
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Shugan, Igor V., Hwung-Hweng Hwung, and Ray-Yeng Yang. "Benjamin-Feir Wave Instability on the Opposite Current." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54084.

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An analytical weakly nonlinear model of Benjamin–Feir instability of a Stokes wave on nonuniform unidirectional current is presented. The model describes evolution of a Stokes wave and its two main sidebands propagating on a slowly-varying steady current. In contrast to the models based on versions of the cubic Schrodinger equation the current variations could be strong, which allows us to examine the blockage and consider substantial variations of the wave numbers and frequencies of interacting waves. Interaction with countercurrent accelerates the growth of sideband modes on a short spatial scale. An increase in initial wave steepness intensifies the wave energy exchange accompanied by wave breaking dissipation, results in asymmetry of sideband modes and a frequency downshift with an energy transfer jump to the lower sideband mode, and depresses the higher sideband and carrier wave. Nonlinear waves may even overpass the blocking barrier produced by strong adverse current. The frequency downshift of the energy peak is permanent and the system does not revert to its initial state. We find reasonable correspondence between the results of model simulations and available experimental results for wave interaction with blocking opposing current.
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Wang, Jinlong, Chunhua Wen, and Wenfeng Zheng. "The Design and Realization of 2.4mm Switch Blocking Programmable Attenuator." In 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT). IEEE, 2018. http://dx.doi.org/10.1109/icmmt.2018.8563947.

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Hriba, Enass, and Matthew C. Valenti. "The Impact of Correlated Blocking on Millimeter- Wave Personal Networks." In MILCOM 2018 - IEEE Military Communications Conference. IEEE, 2018. http://dx.doi.org/10.1109/milcom.2018.8599688.

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Chawla, Arun, and James T. Kirby. "Experimental Study of Wave Breaking and Blocking on Opposing Currents." In 26th International Conference on Coastal Engineering. Reston, VA: American Society of Civil Engineers, 1999. http://dx.doi.org/10.1061/9780784404119.056.

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Reports on the topic "Wave blocking"

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Eckermann, Stephen D. New Approaches to the Parameterization of Gravity-Wave and Flow-Blocking Drag due to Unresolved Mesoscale Orography Guided by Mesoscale Model Predictability Research. Fort Belvoir, VA: Defense Technical Information Center, September 2013. http://dx.doi.org/10.21236/ada597774.

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Eckermann, Stephen D. New Approaches to the Parameterization of Gravity-Wave and Flow-Blocking Drag due to Unresolved Mesoscale Orography Guided by Mesoscale Model Predictability Research. Fort Belvoir, VA: Defense Technical Information Center, September 2011. http://dx.doi.org/10.21236/ada557125.

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Eckermann, Stephen D. New Approaches to the Parameterization of Gravity-Wave and Flow-Blocking Drag due to Unresolved Mesoscale Orography Guided by Mesoscale Model Predictability Research. Fort Belvoir, VA: Defense Technical Information Center, September 2012. http://dx.doi.org/10.21236/ada574451.

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