An experimental investigation of the wall pressure field induced by a low and moderate Mach numbers jet on a tangential flat plate

2018 ◽  
Author(s):  
Matteo Mancinelli ◽  
Roberto Camussi
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Pressure Field ◽  
Wall Pressure ◽  
Mach Numbers

scholarly journals Effect of Area Ratio on Base Pressure in a Suddenly Expanded Duct for Under Expanded Flow ft Mach 1.87

2013 ◽  
pp. 198-202
Author(s):  
M. Ahmed Ali Baig ◽  
Sher Afghan Khan ◽  
Mohammad Yunus Khan
Keyword(s):  
Experimental Investigation ◽  
Mach Number ◽  
Active Control ◽  
Pressure Field ◽  
Area Ratio ◽  
Wall Pressure ◽  
Base Pressure ◽  
Air Injection ◽  
Minimum Length ◽  
Percent Increase

The results of an experimental investigation carried out to control the base pressure in a suddenly expanded axi-symmetric passage is presented in this paper. An active control in the form of micro jets is employed to control the base pressure. Air injection at four locations at the base, symmetric to the nozzle axis is used as the active control. The jet Mach number studied and the area ratios are 1.87, and 2.56, 3.24, 4.84, and 6.25. The L/D ratio is varied from 10 to 1. The experiments are conducted at a fixed level of under expansion (i.e. Pe/Pa = 1.5). In addition to base pressure, wall pressure field along the duct was also measured. As high as 80 percent increase in base pressure was achieved for certain combination of parameters of the present study. The minimum Length-todiameter ratio of the duct required is L/D = 2 for area ratios 6.25 and 4.84. Whereas, this requirement is L/D = 1 for area ratios 2.56 and 3.24.

Effects of Surface Irregularity on Turbulent Boundary Layer Wall Pressure Fluctuations

1984 ◽  
Vol 106 (3) ◽  
pp. 343-350 ◽  
Author(s):  
T. M. Farabee ◽  
M. J. Casarella
Keyword(s):  
Spectral Density ◽  
Flat Plate ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Low Frequency ◽  
Velocity Profiles ◽  
Wall Pressure ◽  
Surface Irregularity ◽  
Wall Pressure Fluctuations ◽  
Frequency Components

Measurements were made of the mean velocity profiles and wall pressure field upstream and downstream of the flow over both a backward-facing and forward-facing step. For each configuration the velocity profiles show that the effects of the separation-reattachment process persist more than 24 step heights downstream of the step. Extremely high values of the RMS wall pressure are measured near reattachment. These values are 5 and 10 times larger than on a smooth flat plate for the backward-facing step and the forward-facing step, respectively. The spectral density of the wall pressure fluctuations in the recirculation region is dominated by low frequency components. Downstream of reattachment there is a reduction in the low frequency content of the wall pressures and an increase in the high frequency components. At the farthest measured position downstream, the spectral density is still higher than that found on a smooth flat plate. These results show that the complex turbulent flow generated by a surface irregularity can significantly increase the localized wall pressure field and these increases persist far downstream of the irregularity. Consequently, a surface irregularity can be a major source of turbulence-induced vibrations and flow noise, as well as a cause of the inception of cavitation in marine applications.

Decay of fluctuating wall-pressure field of Mach 5 turbulent boundary layer

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 1088-1096
Author(s):  
O. H. Unalmis ◽  
D. S. Dolling
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Field ◽  
Wall Pressure
Sign in / Sign up

Export Citation Format

Share Document