1. Numerical analysis of flow over an combat aircraft cavity with venting

2. What is Cavity?

3. Introduction www.marcodebiasi.net www.defence.pk Tone Jones, 2010
Cattafesta, 2008

4. Why Cavity is required?
Image courtesy: U.S. Government [Public domain] via wikipedia.org

5. Techris.in Why Cavity is required?
Image courtesy:

6. Why Cavity is required?

7. Problems

8. Seriousness of the problem
Video Source : Unknown

9. Why control is required?
Stanek, 2005
Cattafesta, 2008

10. Aim Cavities can generate tones upto 170 dB
This can damage electronic equipments and can alter the release of weapon from bay
This self sustained oscillations to be controlled
We propose to design a passive vent near trailing edge

11. How do we do

12. Details
CFD, 2D
Unsteady
Mach 0.8, L/D 5, Ritchie, Knowles, 2005

13. Geometry 32
167.5
162.5
160

14. Grid and boundary conditions

15. Location of pressure history extraction

16. Time domain to frequency domain

17. Vortex clipping

18. OASPL levels
Rear Wall
Downstream wall

19. Correlation

20. Correlation - continued

21. Identification of the location

22. Venting geometry

23. Time history – with venting

24. Velocity vectors – with venting

25. Conclusions
An unsteady RANS based cfd study - to design a passive venting.
Based on the maximum OASPL level on the rear wall and the location of minimum pressure on the downstream wall
Used cross correlation analysis
The baseline cavity was found to oscillate with a tonal amplitude of 155 dB
With controlled case, the oscillation was found to be damped
Future Plan
The study needs to be extended
To 3D
effect of
freestream Mach number
cavity l/d ratio
venting dimensions on the store release characteristics

26. Thank You