Wall pressure fluctuations in a three-dimensional shock-wave/turbulent boundary interaction

AIAA Journal ◽  
1987 ◽  
Vol 25 (1) ◽  
pp. 14-21 ◽  
Author(s):  
D. K. M. Tan ◽  
T. T. Tran ◽  
S. M. Bogdonoff
Keyword(s):  
Shock Wave ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Wall Pressure ◽  
Boundary Interaction ◽  
Wall Pressure Fluctuations

Wall-Pressure Fluctuations Inside Attached Cavitation

2021 ◽  
Author(s):  
Changchang Wang ◽  
Guoyu Wang ◽  
Mindi Zhang ◽  
Qin Wu
Keyword(s):  
Shock Wave ◽  
Shear Layer ◽  
High Frequency ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Cloud Cavitation ◽  
Unsteady Pressure ◽  
Wall Pressure Fluctuations ◽  
Kurtosis Factor ◽  
Skewness And Kurtosis

Abstract This study experimentally investigates the statistics of wall-pressure fluctuations and their source inside attached cavitation under different cavity regimes. Experiments were conducted in the divergent section of a convergent-divergent channel at a constant Reynolds number of Re = 7.8 × 105 based on throat height, and different cavitation numbers σ = 1.18, 0.92, 0.82 and 0.78. Four high-frequency unsteady pressure transducers were flushed-mounted in the divergent section downstream the throat where cavitation develops to sample the unsteady pressure signals induced by cavity behaviors. Flow visualization and wall-pressure measurement in high frequency on the order of MHz were employed using a synchronizing sampling technique. Results are presented for sheet/cloud cavitating flows. Specifically, sheet cavitation with both inception shear layer and fully cavitated shear layer and cloud cavitation under re-entrant jet dominated shedding and shock wave dominated shedding are studied. Compared with re-entrant jet, the interactions between shock wave and cavity could induce pressure peaks with high magnitude within cavity, which will collapse the local vapor along its propagating path and reduce local void fraction. Furthermore, statistics analysis shows that within the cavity, wall-pressure fluctuations increase with the distance to cavity leading edge increase in the first half of cavity length, and the moments of the probability density distribution skewness and kurtosis factor decrease, indicating the asymmetry and intermittency of wall-pressure fluctuation signals decrease. In shock wave dominated cavity shedding condition, the skewness and kurtosis factor increase. These results can provide data to improve the accuracy of turbulence modeling in numerical simulation of turbulent cavitating flow.

The Effect of Aspect Ratio on Wall Pressure Fluctuations at a Wing-Plate Junction

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
M. Awasthi ◽  
J. Rowlands ◽  
D. J. Moreau ◽  
C. J. Doolan
Keyword(s):  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Wide Frequency Range ◽  
Wall Pressure ◽  
Frequency Range ◽  
Three Dimensional Flow ◽  
Wall Pressure Fluctuations ◽  
Aspect Ratios

Abstract Measurements of the wall pressure fluctuations near a wing-plate junction were made for wings with three different aspect ratios (AR) of 0.2, 0.5, and 1.0 at several angles of attack. The chord-based Reynolds number for each wing was 274,000. The results show that the wall pressure fluctuations are a function of wing AR for cases where AR≤ 1.0. For each wing, the pressure fluctuations are highest upstream of the wing leading-edge due to three-dimensional flow separation; wings with AR = 1.0 and 0.5 show comparable levels, while those with AR = 0.2 show lower fluctuation levels over a wide frequency range. Downstream of the leading-edge, the pressure fluctuations decay rapidly on both sides of the wing until the maximum thickness location after which little variation is observed. The pressure fluctuations downstream of the leading-edge on the suction-side were observed to be comparable for AR = 0.2 and 0.5, while those for AR = 1.0 were higher in magnitude. On the pressure-side, the pressure fluctuations near the leading-edge are a weak function of AR; however, those further downstream remain independent of AR. The pressure fluctuations aft of the wing on the suction-side are more coherent for lower ARs and show higher convection velocity, possibly due to an interaction between the tip and the junction flows for lower ARs.

An Experimental Study of the Flow and Wall Pressure Field Around a Wing-Body Junction

1986 ◽  
Vol 108 (3) ◽  
pp. 308-314 ◽  
Author(s):  
M. A. Z. Hasan ◽  
M. J. Casarella ◽  
E. P. Rood
Keyword(s):  
Pressure Gradient ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Low Frequency ◽  
Adverse Pressure Gradient ◽  
Horseshoe Vortex ◽  
Wall Pressure ◽  
Frequency Content ◽  
Wall Pressure Fluctuations

The flow and wall-pressure field around a wing-body junction has been experimentally investigated in a quiet, low-turbulence wind tunnel. Measurements were made along the centerline in front of the wing and along several spanwise locations. The flow field data indicated that the strong adverse pressure gradient on the upstream centerline causes three-dimensional flow separation at approximately one wing thickness upstream and this induced the formation of the horseshoe root vortex which wrapped around the wing and became deeply embedded within the boundary layer. The wall-pressure fluctuations were measured for their spectral content and the data indicate that the effect of the adverse pressure gradient is to increase the low-frequency content of the wall pressure and to decrease the high-frequency content. The wall pressure data in the separated region, which is dominated by the horseshoe vortex, shows a significant increase in the low-frequency content and this characteristic feature prevails around the corner of the wing. The outer edge of the horseshoe vortex is clearly identified by the locus of maximum values of RMS wall pressure.

Numerical Calculation of Wall Pressure Fluctuations in a Centrifugal Fan

2004 ◽  
Author(s):  
Sandra Velarde-Sua´rez ◽  
Rafael Ballesteros-Tajadura ◽  
Juan Pablo Hurtado-Cruz ◽  
Carlos Santolaria-Morros
Keyword(s):  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Power Spectra ◽  
Wall Pressure ◽  
Operating Conditions ◽  
Numerical Code ◽  
Experimental Investigations ◽  
Centrifugal Fan ◽  
Wall Pressure Fluctuations ◽  
Flow Phenomena

In this work, a numerical code has been applied in order to obtain the wall pressure fluctuations at the volute of an industrial centrifugal fan. The numerical results have been contrasted using previous experimental investigations carried out in the same machine. A three-dimensional numerical simulation of the complete unsteady flow on the whole impeller-volute configuration has been carried out using the computational fluid dynamics code FLUENT®. This code has been employed to calculate the time-dependent pressure both in the impeller and in the volute. In this way, the pressure fluctuations in some locations over the volute wall have been obtained. The power spectra of these fluctuations have been calculated, showing an important peak at the blade passing frequency. The amplitude of this peak presents the highest values near the volute tongue, but the spatial pattern over the volute extension is different depending on the operating conditions. The code has successfully simulated the volute pressure fluctuations due to the aerodynamic field, capturing the main flow phenomena such as the jet-wake effects and the impeller-volute interaction.

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