Wavelength Impact on Flow Control through Backward Traveling Wave Oscillations: A Numerical Study

This study investigates the role of wavelength on flow control using surface morphing oscillations. These oscillations are characterized by low amplitude, backward (opposite to the airfoil's forward motion) traveling waves induced on the suction side of the airfoil at 15⁰ angle of attack (AOA), and Reynolds Number (Re) of 50,000. Large eddy simulations (LES) were conducted using the sharp interface curvilinear immersed boundary (CURVIB) method. The wavelength is varied from ƛ* = 0.05 – 0.9 (ƛ* = ƛ/L; ƛ: wavelength, L: airfoil chord length) to simulate different boundary layer thickness and wave generation conditions. A baseline simulation is performed at AOA = 15⁰ and Re = 50,000. Next, the role of wavelength (ƛ* = 0.05 – 0.9) on flow control is explored via traveling waves with an amplitude of a* = 0.001 (a* = a/L; a: amplitude), frequency of f* = 8.0 (f * = fL/U; f: frequency, U: freestream velocity). While our previous results showed that traveling waves of ƛ* =0.44 suppressed stall, the role of wavelength on traveling wave flow control is yet to be understood. This work is supported by National Science Foundation (NSF) grant CBET 1905355, and the computational resources are provided by High Performance Research Computing (HPRC) group at Texas A&M University.