Vibration of and radiated acoustic power from a simply-supported panel excited by a turbulent boundary layer excitation at low Mach number

2019 ◽  
Vol 67 (4) ◽  
pp. 241-251 ◽  
Author(s):  
Mansour Jenzri ◽  
Olivier Robin ◽  
Noureddine Atalia
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Turbulent Boundary Layer ◽  
Acoustic Power ◽  
Low Mach Number ◽  
Simply Supported

Approximate Solution—One-Dimensional Energy Equation for Transient, Compressible, Low Mach Number Turbulent Boundary Layer Flows

1989 ◽  
Vol 111 (3) ◽  
pp. 619-624 ◽  
Author(s):  
J. Yang ◽  
J. K. Martin
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Turbulent Boundary Layer ◽  
Internal Combustion Engines ◽  
Energy Equation ◽  
Numerical Solutions ◽  
Empirical Relation ◽  
Approximate Solutions ◽  
Low Mach Number ◽  
One Dimensional

Unsteady surface heat-flux and temperature profiles in the transient, compressible, low Mach number, turbulent boundary layer typically found in internal combustion engines have been determined by numerically integrating a linearized form of the one-dimensional energy equation. An empirical relation for μt/μ has been used to consider turbulent conductivity. Approximate solutions have been acquired by multiparameter fits to the numerical solutions. Comparisons of the approximate solutions with motored engine experiments show good agreement.

Effects of Flexible Walls on Radiated Sound From a Turbulent Boundary Layer

2002 ◽  
Author(s):  
Z. Charlie Zheng
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Turbulent Boundary Layer ◽  
Sound Radiation ◽  
Low Frequencies ◽  
Low Mach Number ◽  
Wall Pressure Fluctuations ◽  
Flexible Wall ◽  
Flexible Walls ◽  
Radiated Sound

In this paper, radiated sound from low Mach number turbulent boundary layers is studied using Lighthill’s analogy. The focus is to investigate the behavior of wall pressure fluctuations on a flexible wall boundary. Comparisons are made between the results from rigid and flexible walls. At low frequencies, the flexible wall results have shown much higher levels of power spectra. At high frequencies, the spectra of the flexible wall sound radiation and those of the rigid wall sound radiation merge. These trends are in agreement with other experimental and theoretical results in literature. This theoretical study of the two-dimensional turbulent boundary layer can clarify the effects of a flexible wall on radiated sound in low Mach number flows.

scholarly journals Sonic Eddy Model of the Turbulent Boundary Layer

Fluids ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 37
Author(s):  
Paul Dintilhac ◽  
Robert Breidenthal
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Turbulent Boundary Layer ◽  
Skin Friction ◽  
Entrainment Rate ◽  
Square Root ◽  
Reynolds Stresses ◽  
Free Shear Layer ◽  
Velocity Fluctuations ◽  
Acoustic Signaling

The effects of Mach number on the skin friction and velocity fluctuations of the turbulent boundary layer are considered through a sonic eddy model. Originally proposed for free shear flows, the model assumes that the eddies responsible for momentum transfer have a rotation Mach number of unity, with the entrainment rate limited by acoustic signaling. Under this assumption, the model predicts that the skin friction coefficient should go as the inverse Mach number in a regime where the Mach number is larger than unity but smaller than the square root of the Reynolds number. The velocity fluctuations normalized by the friction velocity should be the inverse square root of the Mach number in the same regime. Turbulent transport is controlled by acoustic signaling. The density field adjusts itself such that the Reynolds stresses correspond to the momentum transport. In contrast, the conventional van Driest–Morkovin view is that the Mach number effects are due to density variations directly. A new experiment or simulation is proposed to test this model using different gases in an incompressible boundary layer, following the example of Brown and Roshko in the free shear layer.

Sign in / Sign up

Export Citation Format

Share Document