1- INTRODUCTION: THIS PAPER PRESENTS A 2DV NUMERICAL MODEL FOR NONLINEAR waves BASED ON VOF TECHNIQUE, BY DEVELOPING WISE MODEL. ALTHOUGH WISE [1] USES AN ARBITARY LAGRANGIAN-EULERIAN DESCRIPTION, A STRUCTURED MESH BASED ON EULERIAN DESCRIPTION HAS BEEN UTILIZED FOR SURFACE RECONSTRUCTION. ALTHOUGH THE SET OF EQUATIONS USED IN WISE MODEL IS SECOND ORDER ACCURATE IN TIME AND SPACE, AS ADVECTION PLAYS A MAJOR ROLE IN FLOW CHARACTERISTICS, A FIFTH-ORDER SHAPE FUNCTION IS USED FOR ADVECTION OF VELOCITY FIELD. AFTER DETERMINING water SURFACE, A VOF METHOD IS USED FOR SURFACE RECONSTRUCTION .TO MINIMIZE THE INACCURACIES ASSOCIATED WITH THE ADVECTION OF VOF STEP FUNCTION AND CONSIDERING THE FACT THAT THE ADVECTION SCHEME USED FOR TRANSPORT EQUATION IS NUMERICALLY DIFFUSIVE, YOUNGS’S METHOD IS USED FOR ADVECTION OF THIS FRACTIONAL FUNCTION TO RECONSTRUCT SURFACE MORE ACCURATELY.

1. INTRODUCTION: PERSIAN GULF IS A LARGE SEMI-ENCLOSED BAY LOCATED IN THE MIDDLE EAST AND SURROUNDED BY IRAN, IRAQ, KUWAIT, SAUDI ARABIA, QATAR, BAHRAIN, UNITED ARAB EMIRATES AND OMAN. THE SPECTRUM OF WIND-waves WHICH ARE VERY IMPORTANT FOR THE DESIGN OF MARINE STRUCTURES IS AFFECTED BY THE RELATIVELY SHALLOW water BASIN AND ALSO BY THE SURROUNDING TOPOGRAPHIES.

SHALLOW-water SHIP-waves, KNOWN AS WASH waves, ARE IMPORTANT IN MARINE ENGINEERING. THESE waves CAN AFFECT COASTAL STRUCTURES AND CHANGE NEAR-SHORE MORPHOLOGY. THEY CAN ALSO CAUSE DAMAGE TO SHIP ITSELF IN FINITE DEPTH CHANNELS. THERE ARE DIFFERENT THEORETICAL METHODS TO CONSIDER THESE waves. IN THIS PAPER SHALLOW-water SHIP-waves ARE SIMULATED NUMERICALLY. APPLYING MICHELL’S THIN-SHIP THEORY, FLOW FIELD FAR FROM THE SHIP IS INVESTIGATED. THE RELEVANT SHIP IS CONSIDERED THIN AND CHOSEN FROM SERIES 60. THE NUMERICAL SIMULATION IS PERFORMED IN SUBCRITICAL, CRITICAL AND SUPERCRITICAL REGIMES FOR DIFFERENT DEPTH FROUDE NUMBERS, CONSTANT SHIP SPEEDS AND water DEPTHS. IN THIS STUDY THE FLOW IS CONSIDERED INCOMPRESSIBLE AND IRROTATIONAL. HOWEVER FOR THE ACCURACY OF SIMULATION THE EFFECT OF EDDY VISCOSITY IS THEN CONSIDERED. FURTHERMORE THE EFFECTS OF THE BOUNDARY LAYER ARE CONSIDERED. THE NUMERICAL RESULTS WERE COMPARED WITH OTHER MODELS AND EXPERIMENTAL RESULTS. IT SHOWED THAT MICHELL’S THIN-SHIP THEORY COULD SIMULATE THIS KIND OF waves WITH GRATE ACCURACY AND RELIABILITY.