TY - JOUR

T1 - Instabilities of Transonic Turbulent Flow Over a Flat-Sided Wedge

AU - Kuzmin, A.

PY - 2023

Y1 - 2023

N2 - The transonic turbulent two-dimensional airflow over a symmetric flat-sided double wedge is studiednumerically. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained with ANSYS-18.2 CFXfinite-volume solver of second order accuracy on a fine mesh. The solutions demonstrate an extreme sensitivityof the flow field and lift coefficient to variation of the angle of attack α or free-stream Mach number M∞. Nonunique flow regimes and hysteresis in certain bands of α and M∞ are identified. Interaction of shock wavesand local supersonic regions is discussed. The study confirms a concept of shock wave instability due to acoalescence/rupture of supersonic regions. In addition to the instability of shock wave locations, the numericalsimulation shows a buffet onset, i.e., self-exciting oscillations due to instability of a boundary layer separationat the rear of wedge. Curious flow regimes with positive lift at negative angles α and, vice versa, with negativelift at positive angles α, are pointed out. A piecewise continuous dependence of the lift coefficient on two freestream parameters, α and M∞, is discussed.

AB - The transonic turbulent two-dimensional airflow over a symmetric flat-sided double wedge is studiednumerically. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained with ANSYS-18.2 CFXfinite-volume solver of second order accuracy on a fine mesh. The solutions demonstrate an extreme sensitivityof the flow field and lift coefficient to variation of the angle of attack α or free-stream Mach number M∞. Nonunique flow regimes and hysteresis in certain bands of α and M∞ are identified. Interaction of shock wavesand local supersonic regions is discussed. The study confirms a concept of shock wave instability due to acoalescence/rupture of supersonic regions. In addition to the instability of shock wave locations, the numericalsimulation shows a buffet onset, i.e., self-exciting oscillations due to instability of a boundary layer separationat the rear of wedge. Curious flow regimes with positive lift at negative angles α and, vice versa, with negativelift at positive angles α, are pointed out. A piecewise continuous dependence of the lift coefficient on two freestream parameters, α and M∞, is discussed.

KW - Local supersonic regions

KW - shock waves

KW - Interaction

KW - Boundary-layer separation

KW - oscillations

M3 - Article

VL - 16

JO - Journal of Applied Fluid Mechanics

JF - Journal of Applied Fluid Mechanics

SN - 1735-3572

IS - 1

ER -