DNS study of turbulent energy reduction of laminar streaks due to span-wise oscillation of a flat wall

• Main Author: Prabal SIngh Negi.
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Theses and Dissertations
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/54784
• Institution: Nanyang Technological University

Direct Numerical Simulation (DNS) has been performed to study the effect of span wise wall oscillation on the suppression of turbulent kinetic energy in a single lowspeed laminar streak. An experimental setup for the generation of a single lowspeed boundary layer streak has been numerically simulated. The numerically generated streak is validated against the experimental data and another previously done numerical setup. The downstream evolution of the streak is studied under the effect of span wise wall oscillations. Most recent studies have focussed on the effect of span wise oscillations in a turbulent boundary layer. A recent linearized study [1] has shown substantial turbulent kinetic energy suppression in laminar boundary layer streaks and has left open the question of the effectiveness of wall oscillations on the transition process. In this study we first validate the results of the earlier reported study on the effect wall oscillation on laminar streaks. The study is taken further to higher amplitude oscillations where presumably non-linear effects might become important. The optimum oscillation parameters for turbulence reduction are evaluated which are then used to study the possibility of suppression of transition with wall oscillations.