有限振幅波動下における底面境界層の数値解析

Abstract

Numerical analysis of both laminar and turbulent bottom boundary layers has been performedby applying the finite element method.At first, numerical calculations for laminar bottom boundary layers have been carried out. Theresults show a close agreement with the non-linear theoretical solution deduced by Iwagaki et al.Previously.Next, near-bottom water particle velocities and resultant bottom shear stresses in turbulentboundary layers have been investigated. It is found that bottom friction factors estimated by thenon-linear basic equation are up to five times as large as those calculated by existing formulas.Finally, the numerical results and experimental data on near-bottom water particle velocitieshave been compared. An 'over-shooting' velocity profile which is found noticeably in experimentscan be well represented by applying the present numerical method.