Kazu-hiro Mori

NUMERICAL INVESTIGATION OF FLOW AND THRUST OF AN OSCILLATING 2D HYDROFOIL

The unsteady laminar viscous flow field around a 2D modified NACA 0012 foil is studied numerically. The foil is performing symmetric pitching, heaving and surging oscillations or their combinations. A parametric study is presented by changing the main governing parameters of the motion, although in a limited range of Reynolds numbers. Special attention is payed to the numerical validation and the propulsive abilities of such foil motions. The viscous flow simulation is based on solving the 2D, laminar and incompressible Navier-Stokes equations in a mixed vorticity stream function and vorticity-velocity formulation. An implicit factored finite difference numerical algorithm is used. Numerical tests indicate that the simulate flow is of sufficient accuracy to merit a physical analysis.

Critical Condition for the Appearance of Steady Breakers on 2-dimensional Wave Generated by Submerged Foil

Assuming the steady breaker of an infant stage as a turbulent free-surface flow, a critical condition for its appearance is derived based on the inviscid instability analysis. Besides the curvature of the wave profile, the velocity on the free-surface appears in the condition; the condition is approximately given by

APPROXIMATE PREDICTION OF FLOW FIELD AROUND SHIP STERN BY ASYMPTOTIC EXPANSION METHOD

U/M\,\partial M/\partial x - \,\partial U/\partial x > 0

A Study on Numerical Schemes for More Accurate and Efficient Computations of Free-Surface Flows by Finite Difference Method

where M=KU2-g, K: curvature of the wave, U: velocity on the free-surface, g: gravity acceleration, x: flow direction. The measured data give an acceptable criterion for the appearance of the breaking.