1/5 Scale Model of Aeromot 200S SuperXimango for Scaled Flight Research

International Journal of Flow Control

Fasel²

2013

For Reynolds numbers that are typical for general aviation aircraft separation is typically turbulent. In this paper the question is addressed if flow control strategies that are successful at low-Reynolds number conditions remain effective at higher Reynolds numbers. Towards this end hybrid simulations based on a one-equation renormalization group model were carried out for a modified NACA643-618 airfoil at a chord Reynolds number of one million. For ten degrees angle of attack a short laminar separation bubble develops near the leading edge and the flow separates turbulent from the suction side downstream of the leading edge bubble. Active flow control by harmonic blowing through a spanwise slot was investigated. The control was found to be only mildly effective or even counterproductive. In particular, the disturbances that were introduced by the control were only weakly amplified or even dampened. The unresolved eddy viscosity in the separated boundary layer lowers the effective Reynolds number and makes the flow less unstable or even stable with respect to two-dimensional disturbances. As a consequence of this, higher blowing ratios are required compared to flow control at low-Reynolds number conditions where the shear-layer instability is stronger. *

Section: Reynolds Number and Angle Of Attackmentioning

confidence: 97%

“…The wall boundary condition for the RG model is (8) Walls were considered to be adiabatic. Periodicity conditions were applied in the spanwise direction.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Investigation of Separation Control for Wing Sections

International Journal of Flow Control

Fasel²

2013

“…Several years ago a research project was initiated at the University of Arizona involving dynamically scaled models of general aviation aircraft, 8 such as the Aeromot 200S Super Ximango motor glider, which has a modified NACA 64 3 -618 airfoil (the modified airfoil has a higher maximum lift coefficient than the original NACA 64 3 -618). Two-dimensional (2-D) wing sections were tested in the wind and water tunnel for Reynolds numbers between 64,200 and Re=322,000, the model (1/5 scale) cruise Reynolds number based on MAC.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Separation Control for Wing Sections

6th AIAA Flow Control Conference

Fasel

2012

Self Cite

Numerical simulations of the unsteady separated flow over wing sections at flight Reynolds numbers are challenging. Direct numerical simulations which resolve all scales of the fluid motion promise the highest degree of fidelity but are computationally very expensive. Even large-eddy simulations can be prohibitively expensive because of the high grid resolution required near the walls. Hybrid turbulence models employ Reynolds-averaged NavierStokes near the walls and adjust the turbulence model contribution away from the walls according to the local physical grid resolution. In this paper hybrid simulations based on a one-equation renormalization group model are presented for a modified NACA643-618 airfoil at a chord Reynolds number of 1 million and for 10, 20, and 30 degrees angle of attack. For these conditions a short laminar separation bubble develops near the leading edge and the flow separates turbulent from the suction side downstream of the leading edge bubble. For 10 degrees angle of attack the lift and drag data obtained from the simulations are in good agreement with XFoil predictions and active flow control by harmonic blowing through a spanwise slot upstream of the turbulent separation is investigated.

“…1 The cruise Reynolds number based on mean aerodynamic chord is about 3 Million (depending on altitude) for the full-size and roughly 300,000 for the dynamically scaled model. The latter Reynolds number is well below the design Reynolds number of the NACA 64 3 -618 airfoil and low-Reynolds number effects must be expected.…”

Section: Introductionmentioning

confidence: 99%

Wind Tunnel and Free-Flight Testing of Active Flow Control for Modified NACA 613-618 Airfoil

Dianics

Balthazar

31st AIAA Applied Aerodynamics Conference

et al. 2013

Self Cite

A wing glove for active flow control free-flight experiments using a one-fifth dynamically scaled Aeromot 200S Super Ximango motor glider was developed. The wing glove has a modified NACA 643 − 618 airfoil and is instrumented with off-the-shelf pressure transducers and amplitude-modulated synthetic jet actuators. Before the flight-testing was commenced the wing glove and the instrumentation were tested in two open return low-speed wind tunnels. Due to the low-aspect ratio of the glove, particular attention was paid to the two-dimensionality of the flow field over the wing glove. Several flight experiments were carried out and free-flight data with and without actuation were recorded. Unexpected challenges that were encountered during the flight-testing are discussed and an analysis of the wall pressure data in the frequency domain is provided.