Influence of spatial variation of bottom friction coefficient on tidal dynamics in the Persian Gulf

A modified version of the QUODDY-4 three-dimensional finite element model was used for investigation of spatial distribution of bottom roughness effects on tidal dynamics in the Persian Gulf. A Hydrodynamic approach called Kagan’s method was used to calculate the spatial distribution of bottom friction coefficient for rough, not completely rough and smooth bottoms. This method has reduced disadvantages of hydraulic and semi-empirical approaches and provides a hydrodynamic approach for calculation of bottom friction coefficient using controlling factors of Bottom Boundary Layer and upper than it. Carrying out several numerical simulations and implementation of spatial variation of bottom friction coefficient, it was determined the effect of spatial inhomogeneity of bottom roughness on tidal dynamics in the Persian Gulf. Results show that using spatial variation of computed fiction coefficient instead of constant value to reproduce the tidal dynamics produces considerable changes in determination of tidal amplitudes and the maximum barotropic velocity of M2, S2, K1 and O1 components, while these changes for the tidal phases of mentioned components can be neglected.