EPTT 2020

12th Spring School on Transition and Turbulence

A Study on Three-Dimensional and Isolated Roughness Induced Transition

Submission Author: Ana Elisa Basilio , DF
Co-Authors: Ana Elisa Basilio, Fernando H T Himeno, Marlon Sproesser Mathias, Marcello Augusto Faraco de Medeiros
Presenter: Ana Elisa Basilio

doi://10.26678/ABCM.EPTT2020.EPT20-0121

 

Abstract

The nonlinear instability and transition to turbulent flow are investigated through a Direct Numerical Simulation of a flat plate with a three-dimensional isolated roughness element immersed in a laminar boundary layer flow. The roughness element with height of 0.1 times the boundary layer displacement thickness is located downstream from a disturbance source, which produces two-dimensional Tollmien-Schlichting waves. It is expected that different wave parameters, such as amplitude and frequency, as well as base flow conditions, could yield a wide range of scenarios. Although unable to induce transition to turbulence, this study show the roughness influence on the evolution of the TS waves, such as scattering of the waves into oblique ones and weak distortion of the mean flow.

Keywords

Roughness, boundary layer stability, Laminar-turbulent transition, direct numerical simulation

 

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