EPTT 2020

12th Spring School on Transition and Turbulence

On the Receptivity of Acoustic Waves over Localized Roughness in Compressible Boundary Layer

Submission Author: Pedro Henrique Rosa dos Santos , DF
Co-Authors: Pedro Henrique Rosa dos Santos, Marlon Sproesser Mathias, Fernando H T Himeno, Marcello Augusto Faraco de Medeiros
Presenter: Pedro Henrique Rosa dos Santos

doi://10.26678/ABCM.EPTT2020.EPT20-0072

 

Abstract

Surface imperfections, such as roughness, can affect laminar-turbulent transition process in boundary layers. One main engineering objective is predicting the initial amplitude of instability waves, which is a function of the flow's receptivity to external disturbances. Existing theories about receptivity are limited to restricted flow regimes and semi-empirical relations are commonly used in industry. In this scenario, this work seeks to obtain data about the receptivity of one-dimensional acoustic waves on roughness located in a flat plate boundary layer from direct numerical simulation of the Navier-Stokes equations, which may be extended to a less restricted flow regime. To do so, a sinusoidal velocity perturbation is superimposed on the contour of the base flow. A technique based on a vanishing 2D roughness is applied in order to obtain the instability waves amplitude. The data obtained will be validated with the data from recent experiments which used the same technique.

Keywords

Receptivity, Laminar-turbulent transition, DNS, Tollmien-Schlichting waves

 

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