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Dynamic Simulation and Hydro-elastic Stability Analysis of Flexible Supercavitating Projectiles

Ahmadi Tehrani, Majid | 2022

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 54811 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Dehghani Firouzabadi, Roohallah
  7. Abstract:
  8. At high speeds, cavitation bubbles form at the sharp edges of the submerged body or in situations where the pressure falls below the fluid vapor pressure. By placing a suitable cavitator in the nose of the body, the cavitation bubbles are cobined by increasing the speed and the whole body is placed inside the cavity. The formation of a supercavity leads to a significant reduction in the drag force of the vehicle. The submersible device is in contact with the fluid at two points, the cavitator and the fins, and due to the location of the cavitator in the nose of the body, the forces acting on it play an important role in the stability and control of the device.The main goal of current research is to investigate the stability of Flexible projectile in axial symmetric supercavity. For this purpose, in the first step, a fast method for calculating the unstable hydrodynamic loads on the disk in a two-dimensional symmetric supercavity is proposed. To calculate the unsteady hydrodynamic loads, the potential fluid assumption and the boundary element method have been used. To do this, first the steady supercavity is calculated using an all-nonlinear iterative algorithm. Then, assuming that the amplitude of the disk oscillations is small enough and the frequency of the oscillations is high enough that the changes in length and shape of the supercavity will be very small, the unsteady solution is performed by applying velocity perturbations to the steady supercavity solution.Finally using the proposed model for calculation of unsteady loads and applying them on a Euler-Bernoulli beam the governing equations of FSI model is governed
  9. Keywords:
  10. Supercavitation ; Hydroelasticity ; Stability Analysis ; Fluid-Structure Interaction ; Projectile ; Dynamic Stability

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