Effects of Roughness Strip and Acoustic Sensor Height on Subsonic Boundary Layer by Experiment

2013 ◽  
Vol 421 ◽  
pp. 459-463
Author(s):  
Ning Zong ◽  
Guang Jun Yang ◽  
Jing Sun
Keyword(s):  
Boundary Layer ◽  
Flow Structure ◽  
Dynamic Test ◽  
Acoustic Sensor ◽  
Body Type ◽  
Test Plate ◽  
Spectrum Measurement ◽  
Layer Flow ◽  
Analysis System ◽  
Wind Speed Measurement

According to the measurement requirements of acoustic fatigue load on aft fuselage structure and the external installation restriction of the acoustic sensor on aircraft surface, an acoustic sensor is installed on the silencing jet test plate with reference to body type of the real aircraft. A dynamic test and analysis system combined hot wire wind speed measurement and acoustic spectrum measurement is built up for the combined experiments with different acoustic sensor height and various boundary layer flow structure at subsonic flow condition. Turbulence development of different boundary layer is analyzed. The test result can be coordinated with the local measurement to aircraft flow structure so as to estimate the effect of acoustic sensor on the flow field.

scholarly journals Influence of upstream flow characteristics on the reattachment phenomenon in shallow cavities

2011 ◽  
Vol 15 (3) ◽  
pp. 721-734 ◽  
Author(s):  
Arous Madi ◽  
Amina Mataoui ◽  
Zahia Bouahmed
Keyword(s):  
Boundary Layer ◽  
Flow Structure ◽  
Boundary Layer Flow ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Numerical Approach ◽  
Wall Jet ◽  
Shallow Cavity ◽  
Layer Flow ◽  
Upstream Flow

The influence of the upstream flow characteristics on the behavior of the flow over a shallow cavity and on the reattachment phenomenon is examined in this paper. Accordingly, a comparison of the cavity?s flow structure is performed for two different upstream flows: the wall jet flow and the boundary layer flow. The wall jet possesses a particular structure with two regions: an inner layer analogous to that of a boundary layer and an outer layer similar to that of a free jet; this layer is an additional source of turbulence production in addition to that of the inner shear layer. The present study interested to the effect of this external layer on the shallow cavity?s flow. The numerical approach is based on the low Reynolds stress-omega turbulence model. Fluent 6.3 and the pre-processor Gambit 2.3 are used for the computation. The numerical results indicate that the flow structure is very sensitive to the upstream flow?s characteristics. Indeed, for the same Reynolds number and the same boundary layer thickness at the cavity leading edge, the cavity flow structure in a wall jet upstream flow case differs considerably from that of a boundary layer upstream flow. The most important finding is the earlier reattachment process in the wall jet inflow case, where an important reduction of the reattachment length is observed compared to that of a cavity under a boundary layer flow.

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