Numerical simulation of the laminar-turbulent transition on a swept wing in a subsonic flow

Abstract

A subsonic (U∞=30 m/s) flow around a swept wing with a sweep angle of 45° and a chord of 700 mm aligned at an angle of attack in the test section of the T-324 wind tunnel based at the Khristianovich Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences is considered. The experiments include measuring the static pressure on the model surface and thermal imaging of the laminar-turbulent transition (LTT). The numerical simulations of the laminar flow are performed by means of solving three-dimensional Navier-Stokes equations with the use of the ANSYS Fluent CFD software. The LTT position is determined by an LTT module developed by the authors on the basis of a LOTRAN 3.0 software package. The predicted results agree well with the experimental data and confirm that the favorable pressure gradient in the flow around the wing aligned at an angle of attack of −5° prevents the growth of the Tollmien-Schlichting waves and the LTT on the major part of the upper surface of the wing due to instability of crossflow vortices.