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Richard B. Miles - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation of nanosecond pulsed plasma actuators for control of shock wave boundary Layer Separation
Physics of Fluids, 2018Co-Authors: Kiyoshi Kinefuchi, Andrey Starikovskiy, Richard B. MilesAbstract:This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numerical investigation is undertaken with a large eddy simulation and an energy deposition model for the plasma actuation, in which the dielectric barrier discharge produced plasma is approximated as a high temperature region. The flow characteristics without the plasma actuation correspond to the experimental observation, indicating that the numerical method successfully resolves the shock-wave/boundary-Layer interaction. With the plasma actuation, complete agreement between the experiment and calculation has not been obtained in the size of the shock-wave/boundary-Layer interaction region. Nevertheless, as with the experiment, the calculation successfully demonstrates definite difference between the parallel and canted electrodes: the parallel electrode causes excess heating and increases the strength of the interaction, while the canted electrode leads to a reduction of the interaction strength, with a corresponding thinning of the boundary Layer due to the momentum transfer. The counter flow created by the canted actuator plays an important role in the vortex generation, transferring momentum to the boundary Layer and, consequently, mitigating the shock induced boundary Layer Separation.This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numeri...
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Numerical investigation of nanosecond pulsed plasma actuators for control of shock-wave/boundary-Layer Separation
Physics of Fluids, 2018Co-Authors: Kiyoshi Kinefuchi, Andrey Starikovskiy, Richard B. MilesAbstract:This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numerical investigation is undertaken with a large eddy simulation and an energy deposition model for the plasma actuation, in which the dielectric barrier discharge produced plasma is approximated as a high temperature region. The flow characteristics without the plasma actuation correspond to the experimental observation, indicating that the numerical method successfully resolves the shock-wave/boundary-Layer interaction. With the plasma actuation, complete agreement between the experiment and calculation has not been obtained in the size of the shock-wave/boundary-Layer interaction region. Nevertheless, as with the experiment, the calculation successfully demonstrates definite difference between the parallel and canted electrodes: the parallel electrode causes excess heating and increases the strength of the interaction, while the canted electrode leads to a reduction of the interaction strength, with a corresponding thinning of the boundary Layer due to the momentum transfer. The counter flow created by the canted actuator plays an important role in the vortex generation, transferring momentum to the boundary Layer and, consequently, mitigating the shock induced boundary Layer Separation.This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numeri...
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Magnetically Driven Surface Discharges for Shock-Wave Induced Boundary-Layer Separation Control
45th AIAA Aerospace Sciences Meeting and Exhibit, 2007Co-Authors: Chiranjeev S. Kalra, Sohail Zaidi, Bruce J. Alderman, Richard B. MilesAbstract:This study investigates the impact of a magnetically driven surface plasma column (“snowplow arc”) on shock induced boundary Layer Separation. The surface plasma column appears as a transverse “arc” between two diverging electrodes which is driven by j x B forces so that it sweeps the gas near the surface either in the downstream direction or in the upstream direction. In the experimental setup, an oblique shockwave wave was generated using a ten degree wedge in a Mach 2.8 indraft tunnel. The shock wave impinged on the flat surface in close proximity to the plasma actuator. Experimental results revealed a coupling of the plasma column with the shock – boundary Layer interaction region which resulted in a change in the location of the shock induced boundary Layer Separation point. In case of the body force j x B acting upstream, the Separation point was seen to move upstream. In case of the downstream j x B body force, a very small coupling was observed and the Separation point appeared largely unaffected. Various reasons for the absence of an interaction in the downstream direction are discussed, particularly including the ratio of the scale of the plasma column to the boundary thickness. A sapphire insert with embedded electrodes is under development to allow for a higher current which then may be more effective for the suppression of boundary Layer Separation.
Kiyoshi Kinefuchi - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation of nanosecond pulsed plasma actuators for control of shock wave boundary Layer Separation
Physics of Fluids, 2018Co-Authors: Kiyoshi Kinefuchi, Andrey Starikovskiy, Richard B. MilesAbstract:This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numerical investigation is undertaken with a large eddy simulation and an energy deposition model for the plasma actuation, in which the dielectric barrier discharge produced plasma is approximated as a high temperature region. The flow characteristics without the plasma actuation correspond to the experimental observation, indicating that the numerical method successfully resolves the shock-wave/boundary-Layer interaction. With the plasma actuation, complete agreement between the experiment and calculation has not been obtained in the size of the shock-wave/boundary-Layer interaction region. Nevertheless, as with the experiment, the calculation successfully demonstrates definite difference between the parallel and canted electrodes: the parallel electrode causes excess heating and increases the strength of the interaction, while the canted electrode leads to a reduction of the interaction strength, with a corresponding thinning of the boundary Layer due to the momentum transfer. The counter flow created by the canted actuator plays an important role in the vortex generation, transferring momentum to the boundary Layer and, consequently, mitigating the shock induced boundary Layer Separation.This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numeri...
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Numerical investigation of nanosecond pulsed plasma actuators for control of shock-wave/boundary-Layer Separation
Physics of Fluids, 2018Co-Authors: Kiyoshi Kinefuchi, Andrey Starikovskiy, Richard B. MilesAbstract:This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numerical investigation is undertaken with a large eddy simulation and an energy deposition model for the plasma actuation, in which the dielectric barrier discharge produced plasma is approximated as a high temperature region. The flow characteristics without the plasma actuation correspond to the experimental observation, indicating that the numerical method successfully resolves the shock-wave/boundary-Layer interaction. With the plasma actuation, complete agreement between the experiment and calculation has not been obtained in the size of the shock-wave/boundary-Layer interaction region. Nevertheless, as with the experiment, the calculation successfully demonstrates definite difference between the parallel and canted electrodes: the parallel electrode causes excess heating and increases the strength of the interaction, while the canted electrode leads to a reduction of the interaction strength, with a corresponding thinning of the boundary Layer due to the momentum transfer. The counter flow created by the canted actuator plays an important role in the vortex generation, transferring momentum to the boundary Layer and, consequently, mitigating the shock induced boundary Layer Separation.This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numeri...
Andrey Starikovskiy - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation of nanosecond pulsed plasma actuators for control of shock wave boundary Layer Separation
Physics of Fluids, 2018Co-Authors: Kiyoshi Kinefuchi, Andrey Starikovskiy, Richard B. MilesAbstract:This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numerical investigation is undertaken with a large eddy simulation and an energy deposition model for the plasma actuation, in which the dielectric barrier discharge produced plasma is approximated as a high temperature region. The flow characteristics without the plasma actuation correspond to the experimental observation, indicating that the numerical method successfully resolves the shock-wave/boundary-Layer interaction. With the plasma actuation, complete agreement between the experiment and calculation has not been obtained in the size of the shock-wave/boundary-Layer interaction region. Nevertheless, as with the experiment, the calculation successfully demonstrates definite difference between the parallel and canted electrodes: the parallel electrode causes excess heating and increases the strength of the interaction, while the canted electrode leads to a reduction of the interaction strength, with a corresponding thinning of the boundary Layer due to the momentum transfer. The counter flow created by the canted actuator plays an important role in the vortex generation, transferring momentum to the boundary Layer and, consequently, mitigating the shock induced boundary Layer Separation.This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numeri...
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Numerical investigation of nanosecond pulsed plasma actuators for control of shock-wave/boundary-Layer Separation
Physics of Fluids, 2018Co-Authors: Kiyoshi Kinefuchi, Andrey Starikovskiy, Richard B. MilesAbstract:This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numerical investigation is undertaken with a large eddy simulation and an energy deposition model for the plasma actuation, in which the dielectric barrier discharge produced plasma is approximated as a high temperature region. The flow characteristics without the plasma actuation correspond to the experimental observation, indicating that the numerical method successfully resolves the shock-wave/boundary-Layer interaction. With the plasma actuation, complete agreement between the experiment and calculation has not been obtained in the size of the shock-wave/boundary-Layer interaction region. Nevertheless, as with the experiment, the calculation successfully demonstrates definite difference between the parallel and canted electrodes: the parallel electrode causes excess heating and increases the strength of the interaction, while the canted electrode leads to a reduction of the interaction strength, with a corresponding thinning of the boundary Layer due to the momentum transfer. The counter flow created by the canted actuator plays an important role in the vortex generation, transferring momentum to the boundary Layer and, consequently, mitigating the shock induced boundary Layer Separation.This study numerically explores the flow physics associated with nanosecond pulsed plasma actuators that are designed to control shock-wave induced boundary-Layer Separation in a Mach 2.8 supersonic flow. By using two dielectric barrier surface discharge actuator configurations, parallel and canted with respect to the flow velocity vector, a previous experiment suggested that the actuator worked in two ways to influence the interaction: boundary Layer heating and vorticity production. The heating effect was enhanced with the parallel electrode and made the boundary-Layer Separation stronger, while the canted electrode produced vorticity and suppressed the boundary-Layer Separation due to the momentum transfer from the core flow. Because the detailed physical processes are still unclear, in this paper a numeri...
Yunfei Liu - One of the best experts on this subject based on the ideXlab platform.
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Separate in Latent Space: Unsupervised Single Image Layer Separation
Proceedings of the AAAI Conference on Artificial Intelligence, 2020Co-Authors: Yunfei LiuAbstract:Many real world vision tasks, such as reflection removal from a transparent surface and intrinsic image decomposition, can be modeled as single image Layer Separation. However, this problem is highly ill-posed, requiring accurately aligned and hard to collect triplet data to train the CNN models. To address this problem, this paper proposes an unsupervised method that requires no ground truth data triplet in training. At the core of the method are two assumptions about data distributions in the latent spaces of different Layers, based on which a novel unsupervised Layer Separation pipeline can be derived. Then the method can be constructed based on the GANs framework with self-supervision and cycle consistency constraints, etc. Experimental results demonstrate its successfulness in outperforming existing unsupervised methods in both synthetic and real world tasks. The method also shows its ability to solve a more challenging multi-Layer Separation task.
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AAAI - Separate in Latent Space: Unsupervised Single Image Layer Separation
2020Co-Authors: Yunfei LiuAbstract:Many real world vision tasks, such as reflection removal from a transparent surface and intrinsic image decomposition, can be modeled as single image Layer Separation. However, this problem is highly ill-posed, requiring accurately aligned and hard to collect triplet data to train the CNN models. To address this problem, this paper proposes an unsupervised method that requires no ground truth data triplet in training. At the core of the method are two assumptions about data distributions in the latent spaces of different Layers, based on which a novel unsupervised Layer Separation pipeline can be derived. Then the method can be constructed based on the GANs framework with self-supervision and cycle consistency constraints, etc. Experimental results demonstrate its successfulness in outperforming existing unsupervised methods in both synthetic and real world tasks. The method also shows its ability to solve a more challenging multi-Layer Separation task.
Zhongxuan Luo - One of the best experts on this subject based on the ideXlab platform.
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Knowledge-Driven Deep Unrolling for Robust Image Layer Separation
IEEE Transactions on Neural Networks and Learning Systems, 2020Co-Authors: Risheng Liu, Zhiying Jiang, Xin Fan, Zhongxuan LuoAbstract:Single-image Layer Separation targets to decompose the observed image into two independent components in terms of different application demands. It is known that many vision and multimedia applications can be (re)formulated as a Separation problem. Due to the fundamentally ill-posed natural of these Separations, existing methods are inclined to investigate model priors on the separated components elaborately. Nevertheless, it is knotty to optimize the cost function with complicated model regularizations. Effectiveness is greatly conceded by the settled iteration mechanism, and the adaption cannot be guaranteed due to the poor data fitting. What is more, for a universal framework, the most taxing point is that one type of visual cue cannot be shared with different tasks. To partly overcome the weaknesses mentioned earlier, we delve into a generic optimization unrolling technique to incorporate deep architectures into iterations for adaptive image Layer Separation. First, we propose a general energy model with implicit priors, which is based on maximum a posterior, and employ the extensively accepted alternating direction method of multiplier to determine our elementary iteration mechanism. By unrolling with one general residual architecture prior and one task-specific prior, we attain a straightforward, flexible, and data-dependent image Separation framework successfully. We apply our method to four different tasks, including single-image-rain streak removal, high-dynamic-range tone mapping, low-light image enhancement, and single-image reflection removal. Extensive experiments demonstrate that the proposed method is applicable to multiple tasks and outperforms the state of the arts by a large margin qualitatively and quantitatively.
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ICME - Single Image Layer Separation via Deep Admm Unrolling
2018 IEEE International Conference on Multimedia and Expo (ICME), 2018Co-Authors: Risheng Liu, Zhiying Jiang, Xin Fan, Zhongxuan LuoAbstract:Single image Layer Separation aims to divide the observed image into two independent components according to special task requirements and has been widely used in many vision and multimedia applications. Because this task is fundamentally ill-posed, most existing approaches tend to design complex priors on the separated Layers. However, the cost function with complex prior regularization is hard to optimize. The performance is also compromised by fixed iteration schemes and less data fitting ability. More importantly, it is also challenging to design a unified framework to separate image Layers for different applications. To partially mitigate the above limitations, we develop a flexible optimization unrolling technique to incorporate deep architectures into iterations for adaptive image Layer Separation. Specifically, we first design a general energy model with implicit priors and adopt the widely used alternating direction method of multiplier (ADMM) to establish our basic iteration scheme. By unrolling with residual convolution architectures, we successfully obtain a simple, flexible, and data-dependent image Separation method. Extensive experiments on the tasks of rain streak removal and reflection removal validate the effectiveness of our approach.