The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

A method is presented which enables the computation of the bed-load transport as the product of the saltation height, the particle velocity and the bed-load concentration. The equations of motions for a solitary particle are solved numerically to determine the saltation height and particle velocity. Experiments with gravel particles (transported as bed load) are selected to calibrate the mathematical model using the lift coefficient as a free parameter. The model is used to compute the saltation heights and lengths for a range of flow conditions. The computational results are used to determine simple relationships for the saltation characteristics. Measured transport rates of the bed load are used to compute the sediment concentration in the bed-load layer. A simple expression specifying the bed-load concentration as a function of the flow and sediment conditions is proposed. A verification analysis using about 600 (alternative) data shows that about 77% of the predicted bed-load-transport rates are within 0.5 and 2 times the observed values.

Sediment transport; Part I, Bed load transport

Development and validation of a three-dimensional morphological model

A method is presented which enables the computation of the suspended load as the depth-integration of the product of the local concentration and flow velocity. The method is based on the computation of the reference concentration from the bed-load transport. Measured concentration profiles have been used for calibration. New relationships are proposed to represent the size gradation of the bed material and the damping of the turbulence by the sediment particles. A verification analysis using about 800 data shows that about 76% of the predicted values are within 0.5 and 2 times the measured values.

Sediment Transport, Part II: Suspended Load Transport

A critical review of the intrinsic nature of vortex-induced vibrations

Edge scour at scour protections around offshore wind turbine foundations

Effect of Reynolds Number on Vibrations of Cylinders

This paper summarizes the results of an experimental study which deals with the residual liquefaction of seabed under standing waves. It is shown that the seabed liquefaction under standing waves, although qualitatively similar, exhibits features different from that caused by progressive waves. The experimental results show that the buildup of pore-water pressure and the resulting liquefaction first starts at the nodal section and spreads towards the antinodal section. The number of waves to cause liquefaction at the nodal section appears to be equal to that experienced in progressive waves for the same wave height. Recommendations are made as to how to assess liquefaction potential in standing waves.

Residual Liquefaction Under Standing Waves

When a sediment beach covered by stones or an armor layer is exposed to breaking waves, the turbulence generated by the breaking waves can cause mobilization and removal of the sediment underneath the stones. In two earlier studies by the Technical University of Denmark (DTU)-group, the suction removal of sediments from between armor blocks has dealt with the case of steady current and nonbreaking waves. The present study is an extension of these studies and the results will be presented in a similar way. The critical conditions for removal of sediment are determined. It is found that the onset of removal of sediment is governed by three parameters: (1) the sediment mobility (based on the sediment size, wave height, and wave period), (2) the ratio between the sediment size and the stone size, d/D, and (3) surf similarity parameter, ξ=tan(β)/(H0/L0)0.5. The variation of the critical mobility number for removal of sediment as function of d/D and ξ is determined for the range 0.001<d/D≤1.0 and 0.15<ξ...

Jørgen Fredsøe

Papers

Edge scour at scour protections around offshore wind turbine foundations

Effect of Reynolds Number on Vibrations of Cylinders

Residual Liquefaction Under Standing Waves

Suction Removal of Sediment from between Armor Blocks. III: Breaking Waves

Basic concepts of sediment transport