EXPERIMENTAL AND NUMERICAL INVESTIGATION OF DRAG FORCE REDUCTION OVER UNDERWATER VEHICLES | ||
| The International Conference on Applied Mechanics and Mechanical Engineering | ||
| Article 39, Volume 18, 18th International Conference on Applied Mechanics and Mechanical Engineering., April 2018, Pages 1-14 PDF (1.14 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/amme.2018.34978 | ||
| Authors | ||
| T. A. Ghonim; M. S. Farag | ||
| Lecturer, Dept. of Mech. Power Engineering, Faculty of Engineering, Menoufia University, Egypt. | ||
| Abstract | ||
| ABSTRACT This paper concerns with investigating experimentally and numerically two different methods of drag force reduction over underwater vehicles. The first method is the viscous friction drag reduction by air injection in the near wall layer and the second one is the pressure drag reduction by changing the vehicle nose profile. An experimental test rig was designed and manufactured with all required measurements of drag force and water velocity. Additionally, the experimental work was conducted on six underwater vehicle (torpedo) models with different nose profiles and lengths at variable water velocities. Computational Fluid Dynamic (CFD) simulation was performed using ANSYS. Furthermore, the computations were extended to depict the velocity and pressure contours around two models having different body nose profiles at water velocity of 50 m/s. The total drag forces over eight models were predicted and compared. The numerical results showed good agreement with the experimental ones. The experimental results showed that, for speed range of 1-2.5 m/s the stubbed nose profile had the highest drag. On the other hand, the stepped conical nose profile had the lowest drag force. Moreover, the experimental results of air injection showed a decrease in drag force in the velocity range of 1.7-2.5 m/s but an increase in the drag for velocity range of 1-1.7 m/s was remarked. Finally, there was a significant decrease in drag force of elliptical nose model compared to other models over the velocity range of (0 to 50 m/s). | ||
| Keywords | ||
| Drag force reduction; CFD; Air injection; nose profile; and viscous friction drag | ||
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