Verification, Validation, and Best Practices for a High-Order, Potential-Flow Boundary Element Method

2015 ◽  
Author(s):  
W. James Doyle ◽  
Lauren S. Schambach ◽  
Marc V. Smith ◽  
Charles Field ◽  
Christopher J. Hart

Aegir is a medium-fidelity potential flow code that uses a high-order, non-uniform rational B-Spline (NURBS) based boundary-element method for the computation of steady and unsteady ship hydrodynamics. This paper documents verification and validation for Aegir in its steady-state wave resistance prediction mode and Aegir’s LEAPS to Aegir function. A set of best practice guidelines has been created to aid the user in selecting initial input parameters, which reduces the necessary time for verification. This paper also presents validation of the numerical solution versus physical experiments from publically available ship data sets. Aegir has become more prevalent in the naval ship design community and is now a part of the US Navy’s Integrated Hydrodynamic Design Environment (IHDE).

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1080-1081
Author(s):  
Giuseppe Davi ◽  
Rosario M. A. Maretta ◽  
Alberto Milazzo

2014 ◽  
Vol 644-650 ◽  
pp. 628-631
Author(s):  
Ke Yi Li ◽  
Zhong Cai Pei

When the bubble moves in the vicinity of a free surface, the movement will be affected by the buoyancy and the Bjerknes effect. Blake and Gibson proposed the criterion which determined the motion direction of the jet and the dynamics of bubble. They proposed the jet wouldn’t be formed in the condition that . Based on the potential flow theory, boundary element method (BEM) is used to calculate three typical examples in this paper in order to study the dynamics of the bubble under the combined action of the Bjerknes effect of the free surface and the buoyancy. It is found out during the analysis that the Blake criterion is applicable to predict the conditions that and .


AIAA Journal ◽  
10.2514/2.197 ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1080-1081 ◽  
Author(s):  
Giuseppe Davi ◽  
Rosario M. A. Marretta ◽  
Alberto Milazzo

2015 ◽  
Author(s):  
Amanda J. Costa ◽  
Daniel Kowalyshyn ◽  
Kevin Tuil ◽  
Yin Lu Young ◽  
William Milewski ◽  
...  

This paper presents the results of hydrofoil simulations at varying depths below the free surface, in surface piercing conditions, and integrated with ship hulls. It focuses on the influence of the free surface on the hydrodynamic loads, susceptibility to cavitation, and resulting surface wave patterns. A fast, high-order, NURBS (Non Uniform Rational B-Spline) based boundary element method has been developed that includes both free surface boundary conditions and steady and unsteady iterative pressure Kutta conditions for simulating lift. Results from this method will be compared to published experimental results, analytical solutions based on linear potential theory, and numerical results from viscous simulations obtained using the commercial CFD solver, ANSYS CFX.


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