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Assessment of a fluidic oscillator utilized for active flow control

Event Type: 
Date and Time: 
Friday, May 15, 2015 - 16:00
CTR Conference Room 103
Event Sponsor: 
Parviz Moin, Director of Center for Turbulence Research
Dr. Eran Arad, Head of CFD Group, RAFAEL, Advanced Defense System, Israel Institute of Technology

Active flow control devices and applications received a lot of attention in the recent three decades. While synthetic jets were the preferred technique during the early stages of this practice, fluidic oscillators, also called sweeping jets actuators, were recently in the focus of several research and engineering projects. These actuators bring in the advantages of no-moving-parts and high amplitude signal. However, their control is not straight forward and many times the exact nature of their output is not fully comprehended.

A combined experimental and numerical-simulation study, towards improved understanding of the operation principles, control and output of such a device is currently conducted by US Army AFDD, Tel-Aviv University and Rafael. The current talk focuses on the simulation aspects of this effort.

The internal flow mechanism of a suction and blowing (SOAB) device wasnvestigated using Large Eddy Simulation. The necessity of this level of simulation was queried, followed by comparison with measurements. The simulation results were then utilized to construct a set of functional-fit velocity profiles, to be used as time-dependent boundary conditions for the oscillatory blowing.

Towards implementation of a bank of actuators in a turbulent boundary layer, the separated effects of the actuators output, like suction alone, were investigated within a laminar and turbulent boundary layers. Large eddy simulation was the tool employed for this task also, coupled with wind-tunnels measurements. Interesting aspects of shear enhancement, interaction between suction holes wakes and onset of turbulence were observed.

Dr Arad received his PhD from Aero-Space Engineering, Technion, Israel Institute of Technology on 1994. His thesis focused on turbulence modeling. Dr Arad spent 1994 to 1997 as a Research Fellow at Princeton University, in the computational fluid dynamic group headed by prof A Jameson. His research focused on high efficiency parallel CFD and applications to Large Eddy Simulation. Dr Arad is currently the head of the CFD group of RAFAEL, Advanced Defense Systems, Israel. His research activities include turbulence simulation and modeling, combustion simulation, large scale computing, industrial CFD and active flow control simulation.