Transition prediction in incompressible boundary layer with finite-amplitude streaks

Martin Bautista, Juan Angel and Paredes Gonzalez, Pedro (2015). Transition prediction in incompressible boundary layer with finite-amplitude streaks. In: "6th Symposium on Global Flow Instability and Control", 28 Sep - 2 Oct, Crete, Greece.

Description

Title: Transition prediction in incompressible boundary layer with finite-amplitude streaks
Author/s:
  • Martin Bautista, Juan Angel
  • Paredes Gonzalez, Pedro
Item Type: Presentation at Congress or Conference (Article)
Event Title: 6th Symposium on Global Flow Instability and Control
Event Dates: 28 Sep - 2 Oct
Event Location: Crete, Greece
Title of Book: 6th Global Flow Instability and Control Symposium
Date: 2015
Subjects:
Faculty: E.T.S. de Ingeniería Aeronáutica y del Espacio (UPM)
Department: Matemática Aplicada a la Ingeniería Aeroespacial
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

Modulating the boundary layer velocity profile is a very promising strategy for achieving transition delay, and thus reducing the friction of the plate. An usual way to perform it is by perturbing the flow with counter-rotating vortices that exhibit transient, non-modal growth and lead to streamwise aligned streaks inside the boundary layer, which have been proved (theoretical and experimentally) to be very robust flow structures. Recently, a new mechanism of generating high amplitude streaks has been proposed, consisting on miniature vortex generators (MVGs), increasing considerably the potential stabilization effect. Hence, we propose a numerical tool to analyze the stability properties of the streaky flow without big computational resources. Since streaks depend on how they are generated, and it is linked to the geometric configuration of the surface, a cheap CPU numerical analysis is required in order to perform large parametric studies for streak optimization. For this end, we use the reduced Navier-Stokes (RNS) equations to simulate the nonlinear downstream evolution of finite amplitude streaks in incompressible boundary layer flow. Regarding the stability analysis, the linear three-dimensional Parabolized Stability Equations (PSE-3D) concept constitutes the best candidate for this task. Herein, we present a thorough parametric study of the instability characteristic with respect to critical conditions of the modified incompressible zero-pressure-gradient flat-plate boundary layer by means of finite-amplitude linearly optimal disturbances or streaks. The parameter space is extended from low- to high- amplitude streaks, accurately documenting the transition delay for low-amplitude streaks and the amplitude threshold for streak shear layer instability or bypass transition, which drastically displaces the transition front upstream.

Funding Projects

TypeCodeAcronymLeaderTitle
Government of SpainDPI2013-46403-RUnspecifiedUnspecifiedNuevas técnicas para el análisis de problemas de vibraciones aeromecanicas en turbinas de gas aeronáuticas

More information

Item ID: 42008
DC Identifier: http://oa.upm.es/42008/
OAI Identifier: oai:oa.upm.es:42008
Official URL: http://www.ercoftac.org/special_interest_groups/33_transition_mechanisms_prediction_and_control/past_technical_programme/6thsymposium_onglobal_flow_instability_and_controlseptember_28_-_oc/
Deposited by: Memoria Investigacion
Deposited on: 09 May 2017 09:31
Last Modified: 09 May 2017 09:31
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