Linear parameter-varying active flow control for a 3D bluff body exposed to cross-wind gusts

2014 ◽  
Author(s):  
Jens Pfeiffer ◽  
Rudibert King
Keyword(s):  
Flow Control ◽  
Bluff Body ◽  
Active Flow Control ◽  
Linear Parameter ◽  
Linear Parameter Varying ◽  
Wind Gusts ◽  
Parameter Varying ◽  
Active Flow

scholarly journals Reinforcement learning for bluff body active flow control in experiments and simulations

2020 ◽  
Vol 117 (42) ◽  
pp. 26091-26098
Author(s):  
Dixia Fan ◽  
Liu Yang ◽  
Zhicheng Wang ◽  
Michael S. Triantafyllou ◽  
George Em Karniadakis
Keyword(s):  
Reinforcement Learning ◽  
Fluid Mechanics ◽  
Drag Reduction ◽  
Flow Control ◽  
Bluff Body ◽  
Control Strategies ◽  
Active Flow Control ◽  
Reduction Process ◽  
Automatic Sequence ◽  
Active Flow

We have demonstrated the effectiveness of reinforcement learning (RL) in bluff body flow control problems both in experiments and simulations by automatically discovering active control strategies for drag reduction in turbulent flow. Specifically, we aimed to maximize the power gain efficiency by properly selecting the rotational speed of two small cylinders, located parallel to and downstream of the main cylinder. By properly defining rewards and designing noise reduction techniques, and after an automatic sequence of tens of towing experiments, the RL agent was shown to discover a control strategy that is comparable to the optimal strategy found through lengthy systematically planned control experiments. Subsequently, these results were verified by simulations that enabled us to gain insight into the physical mechanisms of the drag reduction process. While RL has been used effectively previously in idealized computer flow simulation studies, this study demonstrates its effectiveness in experimental fluid mechanics and verifies it by simulations, potentially paving the way for efficient exploration of additional active flow control strategies in other complex fluid mechanics applications.

Drag reduction of a D-shaped bluff-body using linear parameter varying control

2021 ◽  
Vol 33 (7) ◽  
pp. 077108
Author(s):  
T. Shaqarin ◽  
P. Oswald ◽  
B. R. Noack ◽  
R. Semaan
Keyword(s):  
Drag Reduction ◽  
Bluff Body ◽  
Linear Parameter ◽  
Linear Parameter Varying ◽  
Linear Parameter Varying Control ◽  
Parameter Varying

Numerical Analysis of Steady Blowing Based Active Flow Control for Flow Over Ahmed Body

2019 ◽  
Author(s):  
Bansal Shah ◽  
Debashis Basu
Keyword(s):  
Flow Control ◽  
Bluff Body ◽  
Stokes Equations ◽  
Numerical Study ◽  
Active Flow Control ◽  
Control Technique ◽  
Computational Time ◽  
Narrow Slit ◽  
Active Flow ◽  
Ahmed Body

Abstract A numerical study is conducted to investigate fluidic actuation with steady injection for active flow control and drag reduction in an Ahmed body. Numerical results are obtained for the unsteady three-dimensional Navier Stokes equations for both baseline as well as steady injection cases. This study examines the use of active flow control devices at the rear of the 25-deg Ahmed model to reduce drag by controlling an unsteady wake. The present work demonstrates that URANS model with grid refinement at critical locations can accurately describe the aerodynamics around the bluff body with computational time of several days compared to several weeks with traditional LES simulations. In order to modify the wake and reduce the pressure drag, active flow control technique using steady blowing was applied through a narrow slit along all rear edges of the model. The effect of inlet velocity for the baseline simulations was analyzed. Computed Results showed AFC achieves significant reduction in the drag coefficient (Cd) values over the baseline simulations.

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