On the Hydrodynamic of an Impinging Swirling Jet: Effect of the Impingement Distance and the Swirl Number

2009 ◽  
Author(s):  
Mario Felli
Keyword(s):  
Experimental Investigation ◽  
Wall Pressure ◽  
Pressure Measurements ◽  
Swirl Number ◽  
Swirling Jet ◽  
Wall Interaction

The present paper deals with the problem of an impinging swirling jet against a wall. The study concerned a detailed experimental investigation on the jet-wall interaction using velocity and wall pressure measurements in the Large Cavitation Channel of INSEAN. The influence of the impingement distance and the swirl number as well as the interaction between the jet deformation and the perturbation induced on the wall are highlighted in the paper.

A Method for Correcting Wall Pressure Measurements in Subsonic Compressible Flow

1991 ◽  
Vol 113 (2) ◽  
pp. 256-260 ◽  
Author(s):  
C. Ducruet
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Mach Number ◽  
Compressible Flow ◽  
Velocity Gradient ◽  
Static Pressure ◽  
Subsonic Flow ◽  
Diameter Ratio ◽  
Wall Pressure ◽  
Pressure Measurements

A theoretical and experimental investigation has been made of the static pressure hole problem in subsonic flow. Thanks to a linearization, the effects of the boundary layer, of the velocity gradient and of the wall curvature could be separated so that a formula of correction containing three influence functions has been obtained. These functions were determined in the case of practical requirements by means of experiments made on appropriate models for two values of the depth-to-diameter ratio and for at least three values of the Mach number. Then, the method of correction has been applied to the flow around an airfoil at zero angle of attack.

Calculation of tunnel wall interference from wall-pressure measurements

1988 ◽  
Vol 92 (911) ◽  
pp. 36-53 ◽  
Author(s):  
P. R. Ashill ◽  
R. F. A. Keating
Keyword(s):  
Experimental Evaluation ◽  
Solid Wall ◽  
Wall Pressure ◽  
Wind Tunnels ◽  
Pressure Measurements ◽  
Complex Flows ◽  
Tunnel Wall ◽  
Model Flow ◽  
Good Agreement

Summary A method is described for calculating wall interference in solid-wall wind tunnels from measurements of static pressures at the walls. Since it does not require a simulation of the model flow, the technique is particularly suited to determining wall interference for complex flows such as those over VSTOL aircraft, helicopters and bluff shapes (e.g. cars and trucks). An experimental evaluation shows that the method gives wall-induced velocities which are in good agreement with those of existing methods in cases where these techniques are valid, and illustrates its effectiveness for inclined jets which are not readily modelled.

Experimental investigation of aerofoil tonal noise at low Mach number

2021 ◽  
Vol 932 ◽  
Author(s):  
Prateek Jaiswal ◽  
Yann Pasco ◽  
Gyuzel Yakhina ◽  
Stéphane Moreau
Keyword(s):  
Experimental Investigation ◽  
Mach Number ◽  
Three Dimensional ◽  
Normal Modes ◽  
Wall Pressure ◽  
Far Field ◽  
Tonal Noise ◽  
Trailing Edge ◽  
Modal Shape ◽  
Low Mach Number

This paper presents an experimental investigation of aerofoil tones emitted by a controlled-diffusion aerofoil at low Mach number ( $0.05$ ), moderate Reynolds number based on the chord length ( $1.4 \times 10^{5}$ ) and moderate incidence ( $5^{\circ }$ angle of attack). Wall-pressure measurements have been performed along the suction side of the aerofoil to reveal the acoustic source mechanisms. In particular, a feedback loop is found to extend from the aerofoil trailing edge to the regions near the leading edge where the flow encounters a mean favourable pressure gradient, and consists of acoustic disturbances travelling upstream. Simultaneous wall-pressure, velocity and far-field acoustic measurements have been performed to identify the boundary-layer instability responsible for tonal noise generation. Causality correlation between far-field acoustic pressure and wall-normal velocity fluctuations has been performed, which reveals the presence of a Kelvin–Helmholtz-type modal shape within the velocity disturbance field. Tomographic particle image velocimetry measurements have been performed to understand the three-dimensional aspects of this flow instability. These measurements confirm the presence of large two-dimensional rollers that undergo three-dimensional breakdown just upstream of the trailing edge. Finally, modal decomposition of the flow has been carried out using proper orthogonal decomposition, which demonstrates that the normal modes are responsible for aerofoil tonal noise. The higher normal modes are found to undergo regular modulations in the spanwise direction. Based on the observed modal shape, an explanation of aerofoil tonal noise amplitude reduction is given, which has been previously reported in modular or serrated trailing-edge aerofoils.

An experimental investigation on the use of a rectangular strut in a scramjet thruster for thrust vector control

2020 ◽  
pp. 095441002097312
Author(s):  
DR Biju Ben Rose ◽  
BTN Sridhar
Keyword(s):  
Experimental Investigation ◽  
Vector Control ◽  
Wall Pressure ◽  
Laboratory Model ◽  
Ambient Atmosphere ◽  
Pitching Moment ◽  
Force Coefficient ◽  
Side Force ◽  
Thrust Vector Control ◽  
Thrust Vector

An experimental investigation was carried out to find the effect of a strut spanning across the width of a single expansion ramp of a laboratory model scramjet thruster as a thrust vector control device. Cold flow tests were conducted with operating total pressures ranging from 4 bar to 10 bar and the thruster exhaust was to ambient atmosphere. The mass flow rate varied from 0.105 kg/s to 0.263 kg/s. Experiments were conducted by varying the strut height at different operational total pressures to find if any thrust vector control could be achieved to supplement the maneuverability of hypersonic vehicle with aerodynamic control. The laboratory model consisted of an isolator, a divergent combustor followed by a single expansion ramp. Except the side walls, the thruster was fabricated with stainless steel. A high quality acrylic sheet was used for internal flow visualization by a schilieren system. The wall pressure was recorded at different locations from the combustor inlet to ramp trailing edge. Shock pattern was studied from the schilieren images and it was observed that an increase in strut height caused a downward deflection of the exhaust. From the wall pressure distribution, two dimensional side force coefficient and pitching moment coefficient were calculated and the effect of strut height variation on the above coefficients was plotted. Results from experiments indicated that the presence of the strut yielded noticeable changes in side force and pitching moment. The increase in strut height provided exhaust stream directional changes which may be useful in maneuvering the vehicles employing scramjet propulsion system.

Unsteady Wall Pressure Measurements In An Outflow Butterfly Valve Using Remote Microphone Probes

2016 ◽  
Author(s):  
Aurelien Marsan ◽  
Marlene Sanjose ◽  
Yann Pasco ◽  
Stephane Moreau ◽  
Martin Brouillette
Keyword(s):  
Wall Pressure ◽  
Pressure Measurements ◽  
Butterfly Valve
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