Abstract
The hybrid wind tunnel principle is an economical alternative to classical wind tunnels. Wall adaptation tests are reported which are performed in a small scale arrangement duplicating original kinematic relations. A new method for controlling the quality of wall adaptation is presented which is based on the pressure distribution at the rigid wall. This procedure may also be applied for wall adaptation in conventional wind tunnel technique.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- c p :
-
pressure coefficient (=(p−p ∞)/q ∞≈−2u/u ∞)
- d :
-
diameter
- h :
-
height of test section
- k :
-
constant for cross flow pressure drop through perforated wall
- l :
-
length
- Ma :
-
Mach number
- p :
-
pressure
- q :
-
dynamic pressure \(\left( { = \frac{\kappa }{2}pMa^2 } \right)\)
- r :
-
radius
- s :
-
gap width
- t :
-
time
- u, v :
-
disturbance velocity
- w :
-
flow velocity
- x :
-
coordinate in flow direction
- β :
-
Prandtl factor \(\sqrt {1 - {\text{Ma}}_\infty ^{\text{2}} } \)
- δ :
-
boundary layer thickness
- k :
-
ratio of specific heats
- ψ:
-
adaptation coefficient \( = \frac{{c_p }}{{(c_p )_r }}\)
$$ = \left[ {{{\left( {\mathop \smallint \limits^1 c_p^2 (x)dx} \right)} \mathord{\left/ {\vphantom {{\left( {\mathop \smallint \limits^1 c_p^2 (x)dx} \right)} {\left( {\mathop \smallint \limits^1 (c_p )_r^2 (x)dx} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {\mathop \smallint \limits^1 (c_p )_r^2 (x)dx} \right)}}} \right]^{1/2} $$(subcritical flow)
- θ :
-
flow inclination
- λ :
-
shape factor
- μ :
-
Mach angle
- ( ) a :
-
adapted wall (slotted or foam coated, not necessarily optimized)
- ( ) bl :
-
blockage
- ( ) g :
-
gas
- ( ) i :
-
image
- ( ) l :
-
lift
- ( ) m :
-
model
- ( ) r :
-
impermeable rigid wall
- ( )∞ :
-
undisturbed flow
- (¯):
-
mean values
- ( )1;2 :
-
flow ahead and behind an oblique pressure wave
- ( )3 :
-
flow behind a reflected oblique pressure wave
References
AGARD-AR-269 (1990) Adaptive wind tunnel walls. Technology and applications
Ganzer U (1985) A review of adaptive wall wind tunnels. Prog. Aerosp. Sci. 22: 81–111
Garner HC; Rogers EWE; Acum WEA; Maskell EC (1966) Subsonic Windtunnel Wall Corrections. AGARDograph 109
Goethert BH (1961) Transonic wind tunnel testing. Pergamon Press
Hottner Th (1979) Transsonische Umströmungssimulation durch Fahrtwind und Blaswind. Z Flugwiss Weltraumforsch 3: 293–303
Hottner Th (1989) Experimental investigation of a hybrid wind tunnel model. Exp Fluids 7: 464–474
Sears WR; Erickson Jr JC (1988) Adaptive wind tunnels. Ann Rev Fluid Mech 20: 17–34
Wedemeyer E; Heddergott A (1985) The rubber tube test section of the DFVLR in Göttingen. DFVLR-FB-18
Author information
Authors and Affiliations
Additional information
The experimental investigations reported here have been carried out by the following students in the course of undergraduate work: Ch. Bauer, C. Schultes, Th. Reimer and U. Walter. I am very grateful for their great care accomplished contributions.
Rights and permissions
About this article
Cite this article
Hottner, T. Theoretical and experimental investigations of wall adaptation control in wind tunnel and hybrid wind tunnel testing. Experiments in Fluids 19, 233–240 (1995). https://doi.org/10.1007/BF00196471
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00196471