department of hydrodynamic systems project number: 128, 129 contact person: dr. györgy paál...
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Department of Hydrodynamic Systems Project number: 128, 129
Contact person: Dr. György Paál (e-mail: [email protected])
Fluid Flow Flow calculation
Finite-Volume-Method
Time domain
CFX (ANSYS)
CFS++
Acoustics Finite Element Method
Fully Coupled Solution
Time or frequency domain
Coupling Calculation of source terms on fluid mesh
Interpolating source terms onto acoustic mesh
In house code
Hybrid method for aeroacoustic simulations
Department of Hydrodynamic Systems 3
Calculation of the source terms and of the acoustic field
ji
ij
i xx
L
xc
t
2
2
2202
2
d
x
L
x
wd
nwcd
xx
wcd
tw
j
ij
iii I
20
202
2
Lighthill’s wave equation:
Where:
After multiplying with a test function w and some derivation, we arrive at the weak formulation of Lighthill's equation:
ijijjiij cpvvL 20
Department of Hydrodynamic Systems 4
Edge Tone:
plane free jet – wedge interaction
periodic vortex shedding
dipole sound source
model for outside rear-view mirrors or woodwind instruments (project #128)
Cavity Tone:
flow over a cavity
unstable shear layer
interaction with the downstream edge
complex sound source
e.g. flow over gaps on body of a car or sunroof windo(project #128, 129)
Examples for two well-known aeroacoustic configurations
Department of Hydrodynamic Systems 5
Edge tone results
Department of Hydrodynamic Systems 6
Cavity tone