Numerical investigations of the influence of distributed roughness on blasius boundary layer stability

C. Brehm, C. Koevary, T. Dackermann, Hermann F Fasel

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

7 Citations (Scopus)

Abstract

It is well known that surface roughness can have a strong impact on the laminar-turbulent transition process. Whereas for isolated roughness some basic understanding of the physical mechanisms promoting transition has been gathered, the relevant physical mechanisms driving the transition process in the presence of distributed roughness are still far from understood. In this paper the influence of two-dimensional distributed wall roughness on the Blasius boundary layer stability is investigated. Distributed surface roughness is simulated by using an immersed boundary technique. This methodology facilitates the investigation of a large parameter range, regarding size, spacing and shape of the roughness elements, which is relevant for the characterization of distributed wall roughness. Some simulation results are compared to experimental results by Gaster.1 Moreover, it will be demonstrated that these parameters (roughness height, spacing and shape) strongly affect the linear stability characteristics of the boundary layer flow. For example, it was found that small amplitude disturbances experience stronger amplitude growth for sinusoidal roughness elements than for roughness elements with rectangular shape. In addition to investigating the effect of two-dimension roughness on the primary instability we also studied the effect on secondary instabilities.

Original languageEnglish (US)
Title of host publication49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition
StatePublished - 2011
Event49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition - Orlando, FL, United States
Duration: Jan 4 2011Jan 7 2011

Other

Other49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition
CountryUnited States
CityOrlando, FL
Period1/4/111/7/11

Fingerprint

Boundary layers
Surface roughness
Boundary layer flow

ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Brehm, C., Koevary, C., Dackermann, T., & Fasel, H. F. (2011). Numerical investigations of the influence of distributed roughness on blasius boundary layer stability. In 49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition [AIAA-2011-563]

Numerical investigations of the influence of distributed roughness on blasius boundary layer stability. / Brehm, C.; Koevary, C.; Dackermann, T.; Fasel, Hermann F.

49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition. 2011. AIAA-2011-563.

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

Brehm, C, Koevary, C, Dackermann, T & Fasel, HF 2011, Numerical investigations of the influence of distributed roughness on blasius boundary layer stability. in 49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition., AIAA-2011-563, 49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, Orlando, FL, United States, 1/4/11.
Brehm C, Koevary C, Dackermann T, Fasel HF. Numerical investigations of the influence of distributed roughness on blasius boundary layer stability. In 49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition. 2011. AIAA-2011-563
Brehm, C. ; Koevary, C. ; Dackermann, T. ; Fasel, Hermann F. / Numerical investigations of the influence of distributed roughness on blasius boundary layer stability. 49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition. 2011.
@inproceedings{dbf33322f1864316a3dd6b137a05e0ef,
title = "Numerical investigations of the influence of distributed roughness on blasius boundary layer stability",
abstract = "It is well known that surface roughness can have a strong impact on the laminar-turbulent transition process. Whereas for isolated roughness some basic understanding of the physical mechanisms promoting transition has been gathered, the relevant physical mechanisms driving the transition process in the presence of distributed roughness are still far from understood. In this paper the influence of two-dimensional distributed wall roughness on the Blasius boundary layer stability is investigated. Distributed surface roughness is simulated by using an immersed boundary technique. This methodology facilitates the investigation of a large parameter range, regarding size, spacing and shape of the roughness elements, which is relevant for the characterization of distributed wall roughness. Some simulation results are compared to experimental results by Gaster.1 Moreover, it will be demonstrated that these parameters (roughness height, spacing and shape) strongly affect the linear stability characteristics of the boundary layer flow. For example, it was found that small amplitude disturbances experience stronger amplitude growth for sinusoidal roughness elements than for roughness elements with rectangular shape. In addition to investigating the effect of two-dimension roughness on the primary instability we also studied the effect on secondary instabilities.",
author = "C. Brehm and C. Koevary and T. Dackermann and Fasel, {Hermann F}",
year = "2011",
language = "English (US)",
booktitle = "49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition",

}

TY - GEN

T1 - Numerical investigations of the influence of distributed roughness on blasius boundary layer stability

AU - Brehm, C.

AU - Koevary, C.

AU - Dackermann, T.

AU - Fasel, Hermann F

PY - 2011

Y1 - 2011

N2 - It is well known that surface roughness can have a strong impact on the laminar-turbulent transition process. Whereas for isolated roughness some basic understanding of the physical mechanisms promoting transition has been gathered, the relevant physical mechanisms driving the transition process in the presence of distributed roughness are still far from understood. In this paper the influence of two-dimensional distributed wall roughness on the Blasius boundary layer stability is investigated. Distributed surface roughness is simulated by using an immersed boundary technique. This methodology facilitates the investigation of a large parameter range, regarding size, spacing and shape of the roughness elements, which is relevant for the characterization of distributed wall roughness. Some simulation results are compared to experimental results by Gaster.1 Moreover, it will be demonstrated that these parameters (roughness height, spacing and shape) strongly affect the linear stability characteristics of the boundary layer flow. For example, it was found that small amplitude disturbances experience stronger amplitude growth for sinusoidal roughness elements than for roughness elements with rectangular shape. In addition to investigating the effect of two-dimension roughness on the primary instability we also studied the effect on secondary instabilities.

AB - It is well known that surface roughness can have a strong impact on the laminar-turbulent transition process. Whereas for isolated roughness some basic understanding of the physical mechanisms promoting transition has been gathered, the relevant physical mechanisms driving the transition process in the presence of distributed roughness are still far from understood. In this paper the influence of two-dimensional distributed wall roughness on the Blasius boundary layer stability is investigated. Distributed surface roughness is simulated by using an immersed boundary technique. This methodology facilitates the investigation of a large parameter range, regarding size, spacing and shape of the roughness elements, which is relevant for the characterization of distributed wall roughness. Some simulation results are compared to experimental results by Gaster.1 Moreover, it will be demonstrated that these parameters (roughness height, spacing and shape) strongly affect the linear stability characteristics of the boundary layer flow. For example, it was found that small amplitude disturbances experience stronger amplitude growth for sinusoidal roughness elements than for roughness elements with rectangular shape. In addition to investigating the effect of two-dimension roughness on the primary instability we also studied the effect on secondary instabilities.

UR - http://www.scopus.com/inward/record.url?scp=82555201471&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=82555201471&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:82555201471

BT - 49th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

ER -