Evaluation AC1-01

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Front Page

Description

Test Data

CFD Simulations

Evaluation

Best Practice Advice

Aero-acoustic cavity

Application Challenge 1-01 © copyright ERCOFTAC 2004


Comparison of Test data and CFD

Time step sizes have been varied between 4.e-5 and 1.e-5 seconds. For the coarse and fine meshes, the CFD results and comparisons with experiment are presented below in the form of Prms (Figure 5) and sound pressure level, dB (Figure 6) plotted at the 10 measurement points along the cavity floor.


Image011.gif

Figure 5: Prms along the cavity floor – coarse mesh (left) and fine mesh (right)



Image014.gif

Figure 6: Sound Pressure Level (SPL) along cavity floor – coarse (left) and fine mesh (right)



Fourier analysis of the CFD pressure signals for all measurement points indicate that the predictions correctly capture four acoustic tones, three of which are broad band and a dominant narrow band mode. The power spectral density plots are typified by Figure 7 below for node 10.


Future work will concentrate on the following areas


- 3D calculations (assessment of run times and accuracy in anticipation of )

- Assessment of alternative turbulence models

- Optimization of grid and time-step settings.


Image017.gif

Figure 7: PSD vs. frequency for node 10 – coarse mesh (left) and fine mesh (right)

© copyright ERCOFTAC 2004



Contributors: Fred Mendonca; Richard Allen - Computational Dynamics Ltd

Site Design and Implementation: Atkins and UniS


Front Page

Description

Test Data

CFD Simulations

Evaluation

Best Practice Advice