Tollmien-schlichting waves over forward-facing steps: an experimental and numerical study

M. Barahona*, A. F. Rius-Vidales, F. Tocci*, P. Ziegler, S. Hein, M. Kotsonis

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

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Abstract

This work presents an experimental and numerical investigation jointly conducted by TU Delft and DLR on Tollmien-Schlichting (TS) waves interaction with a Forward-Facing Step (FFS). Experiments are conducted at the TU Delft low-turbulence anechoic wind tunnel on an unswept flat plate model. Single-frequency disturbances are introduced using controlled acoustic excitation. The temporal response of the flow in the vicinity of the step is measured using Hot-Wire Anemometry (HWA). In addition, the global effect of the step on laminar-turbulent transition is captured using Infrared Thermography (IR). Two-dimensional (2-D) Direct Numerical Simulations (DNS) performed at DLR provide detailed information at the step. Experimental and DNS results in clean and step case conditions present very good agreement. Both methods predict large distortion of the TS waves downstream of the step, where DNS results present different growth trends between |û| and |(equation presented)| components of the TS waves. Furthermore, negative and positive regions of the production term are observed to correlate with streamwise positions where the disturbances appear tilted in and against the mean shear, respectively. These findings point towards the presence of different growth mechanisms triggered by the step which could modify the level of amplification of disturbances far downstream.

Original languageEnglish
Number of pages6
Publication statusPublished - 2022
Event12th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2022 - Osaka, Virtual, Japan
Duration: 19 Jul 202222 Jul 2022

Conference

Conference12th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2022
Country/TerritoryJapan
CityOsaka, Virtual
Period19/07/2222/07/22

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

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