Control of boundary layer transition over a flat plate using discrete heater strips

In order to improve the aerodynamic performance, there are various flow control methods which can be classified as active and passive. This work aims to conduct a numerical study on the effects of discrete heating, as a mean of an active flow control on the boundary layer transition over a flat plate. Flash-mounted discrete heater strips of various lengths are positioned at appropriate locations on a flat plate surface (corresponding the laminar, transitional and turbulent flow regions) in order to investigate the effects of heating on the skin friction coefficient. Two-and three-dimensional Computational Fluid Dynamics (CFD) simulations are carried out with Ansys-Fluent software using 20 m/s constant inlet velocity with 1 % free stream turbulence intensity and 50 K temperature difference with the free stream on the heater strips subject to constant wall temperature boundary condition on a 2 m long thin flat plate. Recently implemented Menter's k-ω SST (Shear Stress Transport) transition model is employed due to its superiority on predicting laminar to turbulent transition. The transition model validation is determined by comparing the simulation results with the well-known correlation equations and the experimental data for isothermal flat plate conditions. Simulation results revealed that the location and length of the heater strips has a significant effect on the laminar to turbulent transition and aerodynamic performance, and the average skin friction on a flat plate can be reduced by heating.