Session: 08-06-01 non-presentations

Paper Number: 124302

124302 - Coupling a Boundary Element Method With a Boundary Layer Method for Ship Hulls to Predict Separation Points Within the Early Design Stage 

During the process of hull shape optimizations within the early design stage the main demand is to produce quick and reliable results based on few input data. Regarding the calculation of resistance, potential flow solvers are developed and used since many decades because they give reasonable good results within few minutes computation time. The drawback of these solvers is that viscous effects cannot be calculated. Especially the possible flow separation may cost a lot of money and time if it is first detected during the model tests. Therefore an inviscid three dimensional boundary element method is coupled with a viscous two dimensional boundary layer method. The boundary element method KELVIN is developed by Söding and satisfies the body boundary condition in the average over each surface patch by using the potential of point sources. Therefore it is called a patch method. The two dimensional boundary layer method is based on the theory of Prandtl. It is assumed that the direction of the viscous flow within the boundary layer is the same as the outer inviscid flow. Velocity and pressure coefficient along a streamline are evaluated from KELVIN computation. The shape of the ship hull is assumed as an airfoil and the profile for the boundary layer calculations is generated along the streamline. Currently the coupling is a one-way form where the results of the potential flow solver provide the outer flow characteristics and are used to calculate the boundary layer without modifying. The research is carried out within the open software framework E4 which is developed by the Institute of Ship Design and Ship Safety. The results of the boundary layer computation provide the transition point as well as the separation point and the pressure distribution along a streamline on the ship hull. The results are compared with model tests. The aim of the coupling is to provide a tool for the early design stage to assess hull shape optimizations in terms of the main boundary layer phenomena.

Presenting Author: Irene Last Hamburg University of Technology/ Institute of Ship Design and Ship Safety

Presenting Author Biography: B.A. Business Administration at FH Westküste University of Applied Sciences, Heide (2007-2010)
B.Sc. General Engineering Science (Specialization: Naval Architecture) at TUHH University of Technology, Hamburg (2010-2014)
M.Sc. Naval Architecture and Ocean Engineering at TUHH University of Technology, Hamburg (2014-2017)
Institute of Ship Design and Ship Safety, TUHH University of Technology, Hamburg (2017 - today), Research Assistant

Authors:

Irene Last Hamburg University of Technology/ Institute of Ship Design and Ship Safety
Stefan Krüger Hamburg University of Technology/ Institute of Ship Design and Ship Safety