ANALYTIC METHOD FOR INVERSING THE OPEN BOUNDARY CONDITIONS IN A SEMI-CLOSED SEA AREA--CASE I FOR INVERSING THE TIDAL LEVELS AT OPEN BOUNDARY

In this paper,a computational case was employed to describe the computational procedure for inversing the tidal level open boundary conditions using an analytic method.The area for finding the solution is a circular area with a circular arc with the opening angle 60°-being the open boundary and the other circular arc being the solid wall boundary.Proceeding from the reestablished elliptic partial differential equation satisfied by the tidal level function,the extended spectrum method was used to derive the general solution of the equation for the sea of constant depth,and the impermeable solid wall condition(the second class boundary condition)and the adequately specified open boundary conditions were then applied to determine the undetermined coefficients of the general solution,thus obtaining the tidal level distribution function.In this way,both the first and second class boundary values at the solid wall boundary were obtained.With the above boundary values as the boundary conditions,the tidal level values at the open boundary were then inversed by means of the general solution of tidal wave equation.The validity of inversion method could be verified by comparing the inversed tidal level distributions with the originally specified open boundary values.