Transient growth: Experiments, DNS and theory

F. Gökhan Ergin, Meelan Choudhari, Paul Fischer, Anatoli Tumin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

Transient growth of linearly stable disturbances is believed to play an important role in the subcritical transition of laminar boundary layers and the self-sustained nature of boundary layer fluctuations in a fully turbulent flow. Prior work on transient growth has focused on identifying the optimum initial disturbances that result in maximum transient growth. This paper addresses the companion issue of receptivity of those disturbances, the mechanism that determines the actual magnitudes of transient growth that are realized in a given physical situation. A synergistic combination of experimental, computational, and theoretical approaches is used to quantify the flow receptivity to surface roughness in a Blasius boundary layer. Results reveal the non-optimality of the transient growth factors involved as well as the sensitive dependence of flow perturbations to the geometric characteristics of the roughness distribution. Direct numerical simulations (DNS) are compared in detail with experimental results, results obtained from linear receptivity theory and optimal disturbance calculations. DNS shows good agreement with the experimental results. Differences between the linear theory and DNS are attributed to nonlinear receptivity mechanisms. Results also support the proposal by Fransson et al. (2004) that disagreement between optimal disturbances and experiments/DNS may be attributed to differences involving the wall normal location of the streamwise vortex initiating the transient growth.

Original languageEnglish (US)
Title of host publication4th International Symposium on Turbulence and Shear Flow Phenomena
Pages583-588
Number of pages6
Volume2
StatePublished - 2005
Event4th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 4 - Williamsburg, VA, United States
Duration: Jun 27 2005Jun 29 2005

Other

Other4th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 4
CountryUnited States
CityWilliamsburg, VA
Period6/27/056/29/05

Fingerprint

Direct numerical simulation
Experiments
Boundary layers
Surface roughness
Laminar boundary layer
Turbulent flow
Intercellular Signaling Peptides and Proteins
Vortex flow

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes

Cite this

Ergin, F. G., Choudhari, M., Fischer, P., & Tumin, A. (2005). Transient growth: Experiments, DNS and theory. In 4th International Symposium on Turbulence and Shear Flow Phenomena (Vol. 2, pp. 583-588)

Transient growth : Experiments, DNS and theory. / Ergin, F. Gökhan; Choudhari, Meelan; Fischer, Paul; Tumin, Anatoli.

4th International Symposium on Turbulence and Shear Flow Phenomena. Vol. 2 2005. p. 583-588.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Ergin, FG, Choudhari, M, Fischer, P & Tumin, A 2005, Transient growth: Experiments, DNS and theory. in 4th International Symposium on Turbulence and Shear Flow Phenomena. vol. 2, pp. 583-588, 4th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 4, Williamsburg, VA, United States, 6/27/05.
Ergin FG, Choudhari M, Fischer P, Tumin A. Transient growth: Experiments, DNS and theory. In 4th International Symposium on Turbulence and Shear Flow Phenomena. Vol. 2. 2005. p. 583-588
Ergin, F. Gökhan ; Choudhari, Meelan ; Fischer, Paul ; Tumin, Anatoli. / Transient growth : Experiments, DNS and theory. 4th International Symposium on Turbulence and Shear Flow Phenomena. Vol. 2 2005. pp. 583-588
@inproceedings{f88a0026209841b48af50bcf43d75679,
title = "Transient growth: Experiments, DNS and theory",
abstract = "Transient growth of linearly stable disturbances is believed to play an important role in the subcritical transition of laminar boundary layers and the self-sustained nature of boundary layer fluctuations in a fully turbulent flow. Prior work on transient growth has focused on identifying the optimum initial disturbances that result in maximum transient growth. This paper addresses the companion issue of receptivity of those disturbances, the mechanism that determines the actual magnitudes of transient growth that are realized in a given physical situation. A synergistic combination of experimental, computational, and theoretical approaches is used to quantify the flow receptivity to surface roughness in a Blasius boundary layer. Results reveal the non-optimality of the transient growth factors involved as well as the sensitive dependence of flow perturbations to the geometric characteristics of the roughness distribution. Direct numerical simulations (DNS) are compared in detail with experimental results, results obtained from linear receptivity theory and optimal disturbance calculations. DNS shows good agreement with the experimental results. Differences between the linear theory and DNS are attributed to nonlinear receptivity mechanisms. Results also support the proposal by Fransson et al. (2004) that disagreement between optimal disturbances and experiments/DNS may be attributed to differences involving the wall normal location of the streamwise vortex initiating the transient growth.",
author = "Ergin, {F. G{\"o}khan} and Meelan Choudhari and Paul Fischer and Anatoli Tumin",
year = "2005",
language = "English (US)",
volume = "2",
pages = "583--588",
booktitle = "4th International Symposium on Turbulence and Shear Flow Phenomena",

}

TY - GEN

T1 - Transient growth

T2 - Experiments, DNS and theory

AU - Ergin, F. Gökhan

AU - Choudhari, Meelan

AU - Fischer, Paul

AU - Tumin, Anatoli

PY - 2005

Y1 - 2005

N2 - Transient growth of linearly stable disturbances is believed to play an important role in the subcritical transition of laminar boundary layers and the self-sustained nature of boundary layer fluctuations in a fully turbulent flow. Prior work on transient growth has focused on identifying the optimum initial disturbances that result in maximum transient growth. This paper addresses the companion issue of receptivity of those disturbances, the mechanism that determines the actual magnitudes of transient growth that are realized in a given physical situation. A synergistic combination of experimental, computational, and theoretical approaches is used to quantify the flow receptivity to surface roughness in a Blasius boundary layer. Results reveal the non-optimality of the transient growth factors involved as well as the sensitive dependence of flow perturbations to the geometric characteristics of the roughness distribution. Direct numerical simulations (DNS) are compared in detail with experimental results, results obtained from linear receptivity theory and optimal disturbance calculations. DNS shows good agreement with the experimental results. Differences between the linear theory and DNS are attributed to nonlinear receptivity mechanisms. Results also support the proposal by Fransson et al. (2004) that disagreement between optimal disturbances and experiments/DNS may be attributed to differences involving the wall normal location of the streamwise vortex initiating the transient growth.

AB - Transient growth of linearly stable disturbances is believed to play an important role in the subcritical transition of laminar boundary layers and the self-sustained nature of boundary layer fluctuations in a fully turbulent flow. Prior work on transient growth has focused on identifying the optimum initial disturbances that result in maximum transient growth. This paper addresses the companion issue of receptivity of those disturbances, the mechanism that determines the actual magnitudes of transient growth that are realized in a given physical situation. A synergistic combination of experimental, computational, and theoretical approaches is used to quantify the flow receptivity to surface roughness in a Blasius boundary layer. Results reveal the non-optimality of the transient growth factors involved as well as the sensitive dependence of flow perturbations to the geometric characteristics of the roughness distribution. Direct numerical simulations (DNS) are compared in detail with experimental results, results obtained from linear receptivity theory and optimal disturbance calculations. DNS shows good agreement with the experimental results. Differences between the linear theory and DNS are attributed to nonlinear receptivity mechanisms. Results also support the proposal by Fransson et al. (2004) that disagreement between optimal disturbances and experiments/DNS may be attributed to differences involving the wall normal location of the streamwise vortex initiating the transient growth.

UR - http://www.scopus.com/inward/record.url?scp=84867501187&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84867501187&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84867501187

VL - 2

SP - 583

EP - 588

BT - 4th International Symposium on Turbulence and Shear Flow Phenomena

ER -