Experimental transport-rate budgets in complex 3-D turbulent flow near a wing/body junction

Abstract

Experimental flow measurements are presented for a wing–body junction flow obtained using laser-Doppler velocimetry. Mean velocity and Reynolds stress data are used to calculate the complete transport-rate budgets of Reynolds stresses and turbulent kinetic energy. The measurements were carried out in the Virginia Tech Boundary Layer Tunnel at a nominal air speed of 27.5 m/s around a NACA 0020 tail and 3:2 elliptical nose wing shape. Data are presented for a two-dimensional turbulent boundary layer (2DTBL), a strongly skewed three-dimensional turbulent boundary layer (3DTBL), a location in the vicinity of a 3-D separation line, and around the center of the vortex in the horse-shoe vortex that forms around the wing. Terms in the transport-rate equations were calculated also using the measured triple order fluctuating velocity products. Results show that the pressure-diffusion approximated by Lumley [Lumley, J.L., 1978. Computation modeling of turbulent flows. Adv. Appl. Mech. 18, 124–176] is an important term in the balance of v 2 ¯ , uv ¯ , and vw ¯ stress budgets; there were distinct differences between the two-dimensional and three-dimensional turbulent boundary layer budgets. Qualitative comparisons of experimental stress-transport-rate budgets to previous DNS results show a better agreement using the anisotropic dissipation rate of Hallbäck et al. [Hallbäck, M., Groth, J., Johansson, A.V., 1990. An algebraic model for nonisotropic turbulent dissipation rate in Reynolds stress closure, october. Phys. Fluids A 2 (10), 1859–1866].