Numerical Evaluation of 2nd Derivatives of the Potential in the Panel method for the Unsteady Potential Flow Problem

J. Ocean Eng. Technol. 2000;14(3):41-45.

비정상 포텐셜 유동의 패널법 해석에서 포텐셜의 2차 미분값의 수치계산

양진호,전호환

부산대학교 조선해양공학과 대학원(현재 현대선박해양연구소),부산대학교 조선해양공학과 기계기술연구소

Keywords: Unsteady flow analysis, Rankine source method, Double body, Low order panel method, 2nd derivative of potential, Extrapolation

핵심용어: 정상 유동해석, 랜킨소오스법, 이중모형, 저차패널법, 포텐셜의 2차 미분, 외삽법

Abstract

In solving the unsteady potential flow problem of the ship in waves with the panel method, in general one can consider the basic flow as the free stream or double body solution. For the double body solution, the body boundary condition has the 2nd derivatives of the velocity potential. Low order panel methods are known to suffer from the significant error in the 2nd derivatives computed at the body surface. This paper analyzes the numerical error in the 2nd derivatives for a 2-D cylinder and a 3-D sphere problem, and an extrapolation method to obtain the correct derivatives on the body surface is suggested.