Academic literature on the topic 'Towed Array Model'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Towed Array Model.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Towed Array Model"
1
Sullivan, Edmund J. "Model‐based towed array processing." Journal of the Acoustical Society of America 101, no. 5 (1997): 3156. http://dx.doi.org/10.1121/1.419142.
Full text
2
Sullivan, Edmund J., and Geoffrey S. Edelson. "Model‐based broadband towed‐array processing." Journal of the Acoustical Society of America 115, no. 5 (2004): 2577. http://dx.doi.org/10.1121/1.4784220.
Full text
3
Jing, Yun, Rongjun Kang, Jian Ma, Sitong Liu, and Yongwei Liu. "Study on self-noise suppression technique inside towed line array." Journal of Physics: Conference Series 3007, no. 1 (2025): 012071. https://doi.org/10.1088/1742-6596/3007/1/012071.
Full textAbstract:
Abstract Towed line array is an important equipment for long-range detection, but its self-noise seriously affects detection performance. In this paper, a jet release method based on fish slime is proposed to reduce the hydrodynamic noise of towed arrays. The purpose of this method is to reduce the adverse effect of the turbulent pulsating pressure generated by high-speed towed arrays on self-noise and to solve the problem of target signal masking caused by water current noise. An annular nozzle is installed at the front end of the towed array, and slime is sprayed backwards to reduce the turbulent pulsation pressure on the surface of the towed array and improve the signal-to-noise ratio. Large eddy simulations are performed using Fluent and finite element calculations of the acoustic field are conducted using Actran to obtain the flow and acoustic field results, respectively. The viscous drag of the model is reduced after spraying mucus through the nozzle, the surface excitation is remarkably reduced, and the self-noise sound pressure level is substantially reduced. On this basis, experimental tests are conducted in a gravity-type low-noise water hole, and the test results show that the proposed method is indeed effective in reducing the self-noise of towed arrays. The results of this paper lay a technical foundation for the self-noise suppression of towed arrays and have satisfactory reference value.
4
Sullivan, Edmund J., Dieter Brecht, and Leif Persson. "Model‐based towed array processor: Experimental results." Journal of the Acoustical Society of America 107, no. 5 (2000): 2890. http://dx.doi.org/10.1121/1.428744.
Full text
5
Premus, Vincent E., Philip A. Abbot, Vitaly Kmelnitsky, Charles J. Gedney, and Ted A. Abbot. "A wave glider-based, towed hydrophone array system for autonomous, real-time, passive acoustic marine mammal monitoring." Journal of the Acoustical Society of America 152, no. 3 (2022): 1814–28. http://dx.doi.org/10.1121/10.0014169.
Full textAbstract:
An autonomous surface vehicle known as a wave glider, instrumented with a low-power towed hydrophone array and embedded digital signal processor, is demonstrated as a viable low-noise system for the passive acoustic monitoring of marine mammals. Other key design elements include high spatial resolution beamforming on a 32-channel towed hydrophone array, deep array deployment depth, vertical motion isolation, and bandwidth-efficient real-time acoustic data transmission. Using at-sea data collected during a simultaneous deployment of three wave glider-based acoustic detection systems near Stellwagen Bank National Marine Sanctuary in September 2019, the capability of a low-frequency towed hydrophone array to spatially reject noise and to resolve baleen whale vocalizations from anthropogenic acoustic clutter is demonstrated. In particular, mean measured array gain of 15.3 dB at the aperture design frequency results in a post-beamformer signal-to-noise ratio that significantly exceeds that of a single hydrophone. Further, it is shown that with overlapping detections on multiple collaborating systems, precise localization of vocalizing individuals is achievable at long ranges. Last, model predictions showing a 4× detection range, or 16× area coverage, advantage of a 32-channel towed array over a single hydrophone against the North Atlantic right whale upcall are presented for the continental shelf environment south of Martha's Vineyard.
6
Jung, Youngcheol, Woojae Seong, Keunhwa Lee, and Seongil Kim. "A Depth-Bistatic Bottom Reverberation Model and Comparison with Data from an Active Triplet Towed Array Experiment." Applied Sciences 10, no. 9 (2020): 3080. http://dx.doi.org/10.3390/app10093080.
Full textAbstract:
In this paper, a depth-bistatic bottom reverberation model that employs the ray theory is presented. The model can be applied to an active towed array in the ocean. The reverberation time series are modeled under the depth-bistatic assumption and their Doppler shift is calculated based on the actual source–receiver geometry. This model can handle N × 2D range-dependent bathymetry, the geometry of a triplet array, and the Doppler motion of the source, targets, and receiver. The model predictions are compared with the mid-frequency reverberation data measured by an active triplet towed array during August 2015 in the East Sea, Korea. These data are collected with a variable depth source at mid-frequency and the triplet line array in a deep-water environment. Model predictions of the beam time series and its spectrogram are in good agreement with the measurement. In particular, we discuss the effects of the source and receiver depths on the reverberation in deep water observed in both the measured and modeled results.
7
Zhang, Dapeng, Bowen Zhao, and Keqiang Zhu. "Hydrodynamic Response of Ocean-Towed Cable-Array System under Different Munk Moment Coefficients." Sustainability 14, no. 3 (2022): 1932. http://dx.doi.org/10.3390/su14031932.
Full textAbstract:
The ocean towing system plays an important role in the ocean development process. The motion of a towed body is closely coupled with the motion of a towing cable. In this paper, the lumped mass method is used to discrete a towing cable into a lumped mass model. At the same time, on the basis of some assumptions, the relationship between the expression of Munk moments in the classical towed body kinematics and the expression of the Munk moments in the hydrodynamic analysis software OrcaFlex is established. Based on the above assumptions and the derivation, combined with the specific parameters of a certain sea state and a certain towing system, the dynamic simulation of the towing system is made by OrcaFlex. By changing the different Munk moment coefficients, the real-time response of the cable tension and the towed underwater body under different Munk moments is achieved. The effects of different Munk moment coefficients on the change of the tension are obtained; the six degrees of freedom of the towed body under the action of different Munk moment coefficients are shown. To obtain the spectral density of the six degrees of freedom of the towed body under the action of different Munk moment coefficients, Fast Fourier Transform is performed on the calculated results of the towed body in the time domain. The results provide a theoretical basis for the optimal design of a cable and towed body.
8
Su, Zhaohua, Jie Zhuo, and Chao Sun. "Modeling and Data Analysis of Bistatic Bottom Reverberation from a Towed Horizontal Array." Remote Sensing 17, no. 2 (2025): 192. https://doi.org/10.3390/rs17020192.
Full textAbstract:
The spatial-temporal structures of bottom reverberation are associated with seafloor features. In a bistatic bottom reverberation experiment involving a vertical transmitting array and a towed horizontal receiving array, stable stripe structures were observed within the beam-time domain. In this study, a bistatic reverberation model based on ray theory is presented to interpret the experimental phenomena. The conventional empirical scattering function is primarily applicable to small grazing angles. Moreover, the regional segmentation method simulates reverberations across various receiving beams, ignoring scatterers in other areas. To address these issues, we substitute the empirical scattering function with a small-slope approximation (SSA) that is appropriate for full grazing angles. Furthermore, we utilize the beam pattern of arrays to incorporate the effects of each scatterer, and derive the expression for bottom reverberation intensity in both the array and beam domains. The established model demonstrates its applicability in simulating and interpreting the stripe structures of bottom reverberation, and the comparison shows that the model outputs are in agreement with the experimental results. The analysis indicates that the vertical stripes within the structures originate from eigenrays in the mirror reflection direction. Furthermore, the convex stripes are predominantly affected by the direct ray and the surface reflection ray among the scattered eigenrays, whereas the concave and elliptical stripes are primarily affected by the bottom-surface reflection ray and the surface-bottom-surface reflection ray within the scattered eigenrays.
9
Morten, Jan Petter, Jean-Michael Poudroux, and Rune Mittet. "A modeling study of augmenting coarse-grid 3D controlled-source electromagnetics with data from a towed receiver array." GEOPHYSICS 81, no. 1 (2016): E33—E42. http://dx.doi.org/10.1190/geo2014-0583.1.
Full textAbstract:
We have considered the simultaneous 3D inversion of controlled-source electromagnetic data from a towed receiver array and a coarse grid of stationary seabed receivers. Our 3D synthetic model demonstrated the sensitivity and effect on imaging of towed and seabed receiver data. The short-offset data from the towed receivers at 1–3 km offset are effective at resolving a shallow resistor at a 400-m burial depth. On the other hand, the data from the stationary seabed receivers have less noise and will resolve the 3D geometry of resistive structures buried at the 1–2 km depths typical of a hydrocarbon reservoir. We have determined how the complementary sensitivity of data from the two receiver types can be used in simultaneous inversion to recover the shallow and deep resistors.
10
Hui, Juan, An Bang Zhao, Kun Ping Sun, Shao Juan Wen, and Jun Ying Hui. "The Simulation of Tow Ship Noise on Towed Linear Array." Advanced Materials Research 433-440 (January 2012): 2706–11. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.2706.
Full textAbstract:
Based on the acoustical properties of the tow ship noise, this paper studies the effect of tow ship noise on the towed linear array sonar system by computer simulation. The tow ship noise which is fairly approximate to the truth tow ship noise is obtained by the typical mathematical mode simulation firstly. Then the near-filed characteristics of the tow ship noise are simulated by using a simplified channel model. Finally, this thesis studies the interference of tow ship noise through beam-forming. The simulation describes acoustic characteristics of the tow ship noise well, and also provides a good theoretical support for the other simulation systems designs.
Dissertations / Theses on the topic "Towed Array Model"
1
Ekdahl, Filipsson Fabian. "Trajectory and Pulse Optimization for Active Towed Array Sonar using MPC and Information Measures." Thesis, Uppsala universitet, Avdelningen för systemteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-420532.
Full textAbstract:
In underwater tracking and surveillance, the active towed array sonar presents a way of discovering and tracking adversarial submerged targets that try to stay hidden. The configuration consist of listening and emitting hydrophones towed behind a ship. Moreover, it has inherent limitations, and the characteristics of sound in the ocean are complex. By varying the pulse form emitted and the trajectory of the ship the measurement accuracy may be improved. This type of optimization constitutes a sensor management problem. In this thesis, a model of the tracking scenario has been constructed derived from Cramér-Rao bound analyses. A model predictive control approach together with information measures have been used to optimize a filter's estimated state of the target. For the simulations, the MATLAB environment has been used. Different combinations of decision horizons, information measures and variations of the Kalman filter have been studied. It has been found that the accuracy of the Extended Kalman filter is too low to give consistent results given the studied information measures. However, the Unscented Kalman filter is sufficient for this purpose.
2
Stiles, Zachariah H. "Dynamic towed array models and state estimation for underwater target tracking." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37725.
Full textAbstract:
Approved for public release; distribution is unlimited<br>The ability of Towed Linear hydrophone Arrays (TLA) to detect submarine-emitted narrow band tonals makes them the submarine tracking sensor of choice. Recent TLA improvements allow surface ships, Unmanned Underwater Vehicles (UUVs), Unmanned Surface Vehicles (USVs), and submarines alike to detect modern submarines by towing arrays. Allowing the full spectrum of Navy assets access into the Anti-submarine Warfare (ASW) arena is vital to countering future submerged threats. The generation of dynamic TLA and state estimation models in Simulink is detailed in this thesis. The dynamic TLA model receives user-specified TLA parameters and performs Dolph-Chebyshev optimization to form a set of beams which are steered for tracking. The TLA parameters can be specified to meet the needs of the towing vehicle, whether it is a submarine, ship, USV or UUV. The state estimation model uses outputs received from a mobile platform towing an array to estimate the target state. The state estimation model uses both bearing-only and Doppler-bearing Extended Kalman Filters to estimate target state. These models provide a basic platform which can be used to enhance ASW capabilities. Specifically, the models can aid in determining optimal future ASW-asset allocation, improving TLA tracking algorithms, and improving information presented to submarine operators.
3
Sen, Shoham. "Simulation and Study of Noise Generated due to Turbulent Boundary Layer in Towed Hydrophone Array." Thesis, 2016. https://etd.iisc.ac.in/handle/2005/4331.
Full textAbstract:
In this thesis, a wave propagation based analytical model is developed for an underwater towed array. The towed array is modeled as an in finite tube filled with a certain liquid and submerged in an in finite volume of water. This tube is excited by turbulent boundary layer (TBL) excitation which is modeled using both the Corcos and the Chase models. The acoustic response (self-noise) of the towed array is found using the transfer function of the tube and the PSD of the turbulent excitation.
The acoustic response spectrum is compared with the results from the literature. This happens to be the main contribution of the work. This is so because very little literature is available on towed arrays. There is only one analytical work available and our results match exactly with theirs. With respect to experimental results, although there are several articles, numerical values of the tube material properties, the fluid properties and the tube dimensions have not been reported in full. This makes the comparison very difficult. Hence, by doing several parametric studies and investigating properties of materials that were applicable like rubber or Nylon, we have managed to narrow down the parameter ranges and made comparisons with the experimental results.
We have matched single hydrophone TBL response with experimental results from two separate groups. We have had to vary several parameter values in order to do this. The parameters include the Young's Modulus, density, Poisson's ratio and the thickness and diameter of the tube. Also included are the density and the speed of sound of the internal fluid. Sometimes a material from a handbook was chosen that gave a set of parameters. After having matched with the experimental values, the idea was to conduct a parametric study to decide the most influential parameters. We have done this using both the dimensional physical variables as well as non-dimensional variables. We nondimensionalized the equations to help reduce the number of variables in the system and then studied the effect that each parameter has on the noise generated due to Turbulent Boundary Layer developed as a result of the tow. The dominant parameter that influences the TBL response at the hydrophone location is the tube radius a, followed by the Young Modulus E, the density of internal fluid pfi and the thickness h of the tube. An increment in a, E and h reduces the TBL response, while an pfi increment in increases the TBL response.
In addition, several analytical studies were conducted to understand the dispersion characteristics of fluid-_filled submerged tubes. This study is presented in the appendix in order to avoid cluttering the main document. The main idea that emerges from this study is that there is a single real wavenumber in this coupled fluid-structure system which responds at its resonance when the TBL spectrum wavenumber matches the wavenumber value. All other free waves are complex and hence under forced excitation, they do not respond.
Book chapters on the topic "Towed Array Model"
1
Gray, D. A., B. D. O. Anderson, and R. R. Bitmead. "Models for The Application of Kalman Filtering to the Estimation of the Shape of a Towed Array." In Underwater Acoustic Data Processing. Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2289-1_55.
Full text
2
Schneeberger, David, Richard Röttger, Federico Cabitza, et al. "The Tower of Babel in Explainable Artificial Intelligence (XAI)." In Lecture Notes in Computer Science. Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-40837-3_5.
Full textAbstract:
AbstractAs machine learning (ML) has emerged as the predominant technological paradigm for artificial intelligence (AI), complex black box models such as GPT-4 have gained widespread adoption. Concurrently, explainable AI (XAI) has risen in significance as a counterbalancing force. But the rapid expansion of this research domain has led to a proliferation of terminology and an array of diverse definitions, making it increasingly challenging to maintain coherence. This confusion of languages also stems from the plethora of different perspectives on XAI, e.g. ethics, law, standardization and computer science. This situation threatens to create a “tower of Babel” effect, whereby a multitude of languages impedes the establishment of a common (scientific) ground. In response, this paper first maps different vocabularies, used in ethics, law and standardization. It shows that despite a quest for standardized, uniform XAI definitions, there is still a confusion of languages. Drawing lessons from these viewpoints, it subsequently proposes a methodology for identifying a unified lexicon from a scientific standpoint. This could aid the scientific community in presenting a more unified front to better influence ongoing definition efforts in law and standardization, often without enough scientific representation, which will shape the nature of AI and XAI in the future.
3
Valero, Mario M., Adam K. Kochanski, and Craig B. Clements. "Remote characterization of fire behavior during the FireFlux II experiment." In Advances in Forest Fire Research 2022. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_54.
Full textAbstract:
The FireFlux II field experiment was conducted on January 30th, 2013 in south-east Texas, USA, under high fire danger conditions. The experiment was designed to study the behavior of a head fire progressing through a flat, tall grass prairie, and it was informed by the use of a coupled fire-atmosphere model. Vegetation properties and fuel moisture were measured shortly before the experiment. Near-surface atmospheric conditions were monitored during the experiment using an elaborate meteorological instrumentation array. Fire behavior was observed through a combination of remote and in-situ sensors. Clements et al. (2019) presented the analysis of the experiment micrometeorology and in-situ fire behavior observations acquired using a thermocouple array. In this paper, we extend the study of fire behavior during the FireFlux II experiment with the analysis of remote sensing observations. Two thermal infrared and two visible cameras were deployed during the experiment. One thermal and one visible camera were mounted on a helicopter, whereas the other two cameras were installed on a 40-m-height tower next to the burn unit. The tower infrared camera covered a reduced area of interest coincident with the thermocouple array and it allowed monitoring the fire spread as well as measuring the spatially-resolved evolution of brightness temperature. Imagery collected from the helicopter allowed extending fire behavior measurements to the complete burn unit. While airborne IR footage was saturated and did not allow estimation of emitted radiant heat, its analysis allowed tracking fire progression through the plot and therefore estimating rate of spread and fire time of arrival. The existence of in-situ temperature observations provides an outstanding opportunity to validate remote sensing methodologies. In addition, the combination of remote observations with in-situ temperature measurements allows a comprehensive characterization of fire behavior, including spatially-resolved fire rate of spread and fire time of arrival, fire radiative power, Byram’s fire line intensity, and air temperature during fire front passage. The current version of this paper presents preliminary results from this analysis. Such results demonstrate the usefulness of the selected datasets and the potential of the proposed methodology, encouraging further work. Possible applications of the resulting dataset include (i) the validation of existing fire behavior models that are able to predict any of the measured variables, (ii) the development of data-driven fire behavior models, and (iii) the investigation of the relative contribution of radiative and convective heat transfer mechanisms to fire spread.
Conference papers on the topic "Towed Array Model"
1
Loomis, Jean, Jaye Falls, and Sarah Mouring. "Measured and Predicted Response of a Submerged Towed Sonar Array to Maneuvering Input." In Vertical Flight Society 71st Annual Forum & Technology Display. The Vertical Flight Society, 2015. http://dx.doi.org/10.4050/f-0071-2015-10222.
Full textAbstract:
There exists a necessity to increase helicopter pilot's safety during mine countermeasure operations. Models have been developed for scenarios involving a cable that is fully submerged in either air or water, but there has been very little testing when the cable is partially submerged. This change in fluid type along the length of the cable has a significant impact on the stability and drag forces that has not yet been extensively studied. A series of experimental investigations examining speed, acceleration, length of cable and path of motion were paired with predictions from a simulation for the purpose of developing a predictive tool. It was determined that the simulation accurately predicted the depth of the body and its position behind the tow point; however, the simulation did not accurately predict the lateral motion of the body. Additionally, these tests further characterized the stability of the body, indicating that acceleration is a governing factor in the operability of the towed sonar.
2
Sullivan, Edmund J., Jason D. Holmes, and William M. Carey. "Model-Based Processing for a Short Towed Array." In 2006 IEEE Nonlinear Statistical Signal Processing Workshop. IEEE, 2006. http://dx.doi.org/10.1109/nsspw.2006.4378816.
Full text
3
Seto, Mae L., and Christopher D. Williams. "Modeling of a Towed Array: Scale Model Experiments and Numerical Simulations." In SNAME 29th American Towing Tank Conference. SNAME, 2010. http://dx.doi.org/10.5957/attc-2010-014.
Full textAbstract:
This paper looks at developing a numerical model of a ship and its tow system as the tow system is winched in during high sea states. The focus is on the vertical plane dynamics with the ship and tow system moving at constant heading and constant speed. The goal is to develop the Ship-Tow Interaction in Sea State (STISS) model to determine, for e.g. whether the tow system can be winched in / out without interacting with any part of the transom. STISS makes it possible to decide for a given tow system what ships of opportunity can be used as the tow platform based on only static characteristics of the tow, the tow depth as a function of scope and speed, ship transom geometry, and the ship RAOs. A unique blend of model scale tests and numerical modeling is used to help develop the STISS model. Semi-captive scale model tests of the ship with a deployed tow system were performed in a flume tank to provide validation data for up to 10 knots full scale. The partially validated STISS predictions appear reasonable and the model is awaiting full scale validation. The ability to make predictions for this complex tow condition has not been reported in the literature.
4
Karkee, Manoj, Madhu Monga, Brian L. Steward, Joseph Zambreno, and Atul G. Kelkar. "Real-Time Simulation and Visualization Architecture With Field Programmable Gate Array (FPGA) Simulator." In ASME 2010 World Conference on Innovative Virtual Reality. ASMEDC, 2010. http://dx.doi.org/10.1115/winvr2010-3772.
Full textAbstract:
Real-time simulation of dynamic vehicle system models is essential to facilitate advances in operator and hardware in the loop simulation and virtual prototyping. Real-time virtual reality-based simulation enables users to visualize and perceive the effect of their actions during the simulation. As model complexity is increased to improve the model fidelity, the computational requirements will also increase, thus increasing the challenge to meet real-time constraints. A distributed simulator architecture was developed for off-road vehicle dynamic models and 3D graphics visualization to distribute the overall computational load across multiple computational platforms. This architecture consisted of three major components: a dynamic model simulator, a virtual reality simulator, and an interface to controller and input hardware devices. The dynamic model simulator component was developed using Matlab/Simulink Real Time Workshop on a PC and also using Field Programmable Gate Arrays (FPGA), which offered a highly parallel hardware platform. The simulator architecture reduced the computational load to an individual platform and increased the real-time simulation capability with complex off-road vehicle system models and controllers. The architecture was used to develop, simulate and visualize a tractor and towed implement steering dynamics model. The model also included a steering valve subsystem which contained very high frequency hydraulic dynamics and required 10 μs integration time step for numerical stability. The real-time simulation goal was not achievable for the model with this level of complexity when the PC-based simulator was used. However, the FPGA-based simulator achieved a real-time goal taking only 2 μs to complete one integration time step.
5
Chang, P. A., T. J. Ratcliffe, J. R. Rice, and S. McGuigan. "Two Novel Free Surface Measurement Techniques Developed at DTMB." In SNAME 23rd American Towing Tank Conference. SNAME, 1992. http://dx.doi.org/10.5957/attc-1992-027.
Full textAbstract:
Capacitance wave probes have been traditionally used at DTMB for measuring the wave heights in the Kelvin wake of towed surface ship models. Two new wave height measurement systems have recently been developed at DTMB: a laser wave height probe, using a linear array of charged couple devices, and a surface sensing mechanical probe. These devices represent improvements to the capacitance probes in the form of reduced and/or eliminated susceptibility to contamination and increased frequency response. In this paper, the physics of operation of the measurement systems and design considerations for their optimization will be discussed. Measurements of the free surface in a regular wave field, and for longitudinal wavecuts with a ship-model, over a wide Froude number range, have been made. Based on experimental results, evaluations of the various attributes and shortcomings of each type of probe will be made.
6
Bang, Hyung-Joon, Hong-Il Kim, Moonseok Jang, and Jae-Hung Han. "Tower Deflection Monitoring of a Wind Turbine Using an Array of Fiber Bragg Grating Sensors." In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5033.
Full textAbstract:
This paper introduces a fiber Bragg grating (FBG)-based sensing system for the multi-MW scale wind turbine health monitoring, and describes the results of field tests of dynamic strain monitoring and the deformed shape estimation of the wind turbine tower structure. An FBG interrogator was developed with a spectrometer-type demodulator based on a linear photo detector. Real-time shape estimation of the wind turbine tower was accomplished using strain data gathered by surface mounted fiber Bragg grating sensors. The finite element model of the wind turbine tower was created and the displacement-strain transformation (DST) on the basis of the modal approach was obtained. The time histories of the strain were gathered for the cases of blade stop and start using the FBG sensors located at the upwind side of the tower. Finally, the full deflection shapes of the tower were successfully estimated using arrayed FBG sensors.
7
Rand, Richard H., Deepak V. Ramani, William L. Keith, and Kimberly M. Cipolla. "The Quadratically-Damped Mathieu Equation and Its Application to Submarine Dynamics." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1764.
Full textAbstract:
Abstract This work is motivated by naval use of passive towed sonar arrays of hydrophones. We consider the simplest model of a towed mass. The mass is considered to move only in a horizontal direction x perpendicular to the tow direction. The tension in the tow cable is expected to be nonconstant due to turbulence, and is modeled by a sinusoidal forcing function. The resulting differential equations are analyzed for linear stability and nonlinear dynamical effects. In particular we study the nonlinear dynamics of the ODE: x ¨ + ( δ + ϵ cos t ) x + x ˙ | x ˙ | = 0
8
Rios, Jaime, Carlos Velazquez, Teddy Rakotomanana, Mehdi Kabir, and Jiajun Xu. "Generative Design of a Novel Additively Manufactured Solar Array System for Powering Space Equipment on the Lunar Surface." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71221.
Full textAbstract:
Abstract The moon poses harsh conditions including excessively cold 14-day nights in some locations. However, the South Pole of the moon receives sunlight 100% of the time in summer and 70% of the time in Winter. NASA is, therefore, seeking to land at the South Pole by 2024 under Artemis missions and deploy solar arrays to power landers, rovers, and other equipment in order to facilitate a sustainable presence on the moon. Artemis project also seeks to lay the groundwork for a crewed mission to the Mars. To meet the NASA needs for Artemis mission, the desired solar array system is required to cover a large surface area to maximize the capture of solar irradiance when the arrays are deployed 10 meters above the lunar terrain. Additionally, the design must be lightweight, capable of being redeployed and retracted with minimal human interaction, and can withstand lunar dust, radiation, and extreme temperatures. In the present study, a scale-down working model of the prototype (1:10th scale) is introduced with a particular emphasis on the mechanical mechanisms of telescopic boom, tower, and deployment/retraction of solar arrays. The solar arrays are encased in a cylinder that sits atop the telescopic boom and can be deployed irrespective of the boom height. This study attempts to use principles of Geometric Origami to create a novel structural design that allows for a large-diameter array to be rigid without a supporting skeletal structure. By removing the rigid supporting structure, the design becomes highly portable and easily packable and deployable. Once the design is finalized, Fusion360’s Generative Design Suite will be used to optimize the strength-to-weight ratio and manufacturability. Conducting topology optimization based on finite element modeling to meet the required criteria on the weight, strength, durability, and rigidity leads often to irregular geometries which are not possible to be fabricated using conventional manufacturing. However, additive manufacturing features the ability to develop and fabricate the proposed innovative design.
9
Mu, Baojie, Yaoyu Li, Timothy I. Salsbury, and John M. House. "Extremum Seeking Based Control Strategy for a Chilled-Water Plant With Parallel Chillers." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9949.
Full textAbstract:
Chilled-water plants with multiple chillers are the backbone of ventilation and air conditioning (VAC) systems for commercial buildings. A penalty function based multivariate extremum seeking control (ESC) strategy is proposed in this paper for maximizing the energy efficiency in real time for a variable primary flow (VPF) chilled-water plant with parallel chillers. The proposed ESC algorithm takes the total power consumption (chiller compressors + cooling tower fan + condenser water pumps + penalty terms if inputs saturation occurs) as feedback, and tower fan air flow, condenser water flows and evaporator leaving chilled-water temperature setpoint as plant inputs (ESC outputs). A band-pass filter array is used in place of the conventional high-pass filter at the plant output so as to reduce the cross-channel interference. Chiller sequencing is also enabled with input saturation related signals. A Modelica based dynamic simulation model is developed for a chilled-water plant with two parallel chillers, one cooling tower, one air-handling unit and one zone. Simulation results under several testing conditions validate the effectiveness of the proposed model-free control strategy, as well as the significant energy saving.
10
Larsen, Allan, Yasutsugu Yamasaki, Hyunsok Choi, Dincer Mete, and Inger B. Kroon. "1915 Çanakkale Bridge - Aerodynamic Investigations." In IABSE Symposium, Istanbul 2023: Long Span Bridges. International Association for Bridge and Structural Engineering (IABSE), 2023. http://dx.doi.org/10.2749/istanbul.2023.0790.
Full textAbstract:
<p>With a world record main span length of 2023 m the design of the 1915 Çanakkale Bridge spanning the Çanakkale Strait, Türkiye, warranted an extensive array of aerodynamic investigations carried out for determination of the wind loading and verification of the aerodynamic performance. Also, the paper reviews the development of the design specifications considering the location of the bridge and available meteorological data. The development of the wind tunnel test programme necessary to verify the specifications and obtain input to the bridge design is reviewed and selected key results presented. The wind tunnel tests discussed included section model tests of the bridge girder and towers, full aeroelastic models of the free-standing tower and full bridge in service and section model tests of the hanger cables for clarification of rain / wind and vortex induced vibrations. Concerning flutter stability of the bridge it was found that the twin-box girder design provided a high critical wind speed for onset of flutter linked to the progress of the aerodynamic moment coefficient. Vortex induced vibrations of the hanger cables were found to be less pronounced than proposed by Eurocode whereas rain / wind vibrations were substantially stronger.</p>