Calculation of Linear Added mass Coefficients for a submerged vehicle Using Numerical and Analytical Methods

Added mass is the virtual additional mass of an object when it is accelerated relative to the surrounding fluid. The present paper documents both numerical and analytical methods for computing the added mass coefficients of submerged vehicles. A new numerical method is described to calculate the linear coefficients in axial and lateral directions. The method is firstly validated by comparing its results with the known results for a sphere. Numerical results show that the added mass coefficients are independent from accelerations values. In addition, an analytical method which is called equivalent ellipsoid is explained to approximate the added mass coefficients. In this approach, various components of vehicle are separately replaced by ellipsoids whose dimensions are optimally determined by measuring the moments of inertia. Comparison of the obtained results with available and published experimental reports of DARPA SUBOFF submarine shows the simplicity and accuracy of the numerical and even analytical approaches

Keywords:

Added Mass , Submarine , Linear Accelerated Motions , Equivalent Ellipsoids