1. COMPARISON STUDY OF SUPERCAVITATION PHENOMENA ON DIFFERENT PROJECTILES SHAPES IN TRANSIENT FLOW BY CFD Prof. Magdy Abu Rayan Mechanical Power Department, Mansoura University, Egypt Prof. Nabil H. Mostafa Mechanical Power Department, University, Zagazig, Egypt Dr. Mohamed H. Mansour Mechanical Power Department, Mansoura University, Egypt Eng. Mohsen Y. Mansour Aeronautical Eng., Mansoura University, Egypt 1

2. Supercavitation 2

3. Introduction Cavitation Definition – Vapor Pressure – Cavitation Coefficient Superavitation Definition Supercavitation Facts 3

4. Cavitation Definition Cavitation is the occurrence of vapor in a fluid due to local low pressures which are generated by high local flow velocities.(Hammit,1970) Vapor Pressure Force exerted by the gas or vapor released by a liquid in container or space. Vapor pressure is a relative measure of the tendency to evaporate (volatility) 4

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6. 6 Grids over the four projectiles 1- Hemispherical 2- Telescopic 3- Blunt 4- Conical

7. Flow Simulation upon Projectiles 1-a- Hemispherical Using Structured Grid Supercavitating cavities formation upon hemisphrical projectile at speed 60 m/s, using structured mesh domain. 7

8. Flow Simulation upon Projectiles 1-b- Hemispherical, Unstructured Supercavitating cavities formation upon hemisphrical projectile at speed 60 m/s, using unstructured mesh domain. 8

9. Flow Simulation upon Projectiles 2-b- Telescopic, Structured Supercavitating cavities formation upon telescopic projectile at speed 60 m/s, using structured mesh domain. 9

10. Flow Simulation upon Projectiles 2-b- Telescopic, Unstructured Supercavitating cavities formation upon telescopic projectile at speed 60 m/s, using unstructured mesh domain. 10

11. Flow Simulation for Blunt Projectile 3-a- Blunt, Structured Supercavitating cavities formation upon blunt projectile at speed 60 m/s, using structured mesh domain. 11

12. Flow Simulation for Blunt Projectile 3-b- Blunt, Unstructured Supercavitating cavities formation upon blunt projectile at speed 60 m/s, using unstructured mesh domain. 12

13. Flow Simulation upon Projectiles 4-a- Conical, Structured Supercavitating cavities formation upon blunt projectile at speed 60 m/s, using structured mesh domain. 13

14. Flow Simulation upon Projectiles 4-b- Conical, Unstructured Supercavitating cavities formation upon conical projectile at speed 60 m/s, using unstructured mesh domain. 14