Scour around pipelines, piles and sea walls

Review of knowledge regarding scour near pipelines and other offshore structures.

Nonparametric and Parametric Estimation of Wave Statistics and Spectra

A nonparametric bivariate density estimation technique is developed employing tensor product B-splines to provide a concise wave data summary. Most of the existing nonparametric techniques involve a certain level of subjectivity in the choice of smoothing parameters. A criterion based on the least squares concept is proposed to remove the...

Effect of Wave-Current Interaction on the Wave Parameter

The interaction of a gravity wave with a steady uniform current is discussed in this paper. Analysis indicates there is no dominant difference in the results obtained when employing either the equation of conservation of wave energy flux or the equation of conservation of wave action flux. Numerical calculations of the wave length change by...

Estimation and Analysis of Horizontal Bottom Velocities Due to Waves

Maximum bottom velocities caused by waves were calculated using digital computers. Four wave theories, Airy, Stokes third order, Cnoidal and Solitary,were applied in the computation. Results of the study were tabulated and presented graphically to highlight the importance of various parameters affecting the maximum bottom velocity. It is...

Mathematical Model to Predict the Behavior of Deep-Draft Vessels in Restricted Waterways

Presently deep-draft navigation channel analysis, design and review is based on empirically derived ratios of the design vessel's dimensions. Because of radical changes in vessel operation purposes and characteristics, these ratios can no longer be safely or economically applied. The mathematical model and related theory described in this...

Sediment Movement Induced by Ships in Restricted Waterways

A numerical model using the momentum theory of the propeller and Shields' diagram was developed to study sediment movement induced by a ship's propeller in a restricted waterway. The velocity distribution downstream of the propeller was simulated by the Gaussian normal distribution function. The shear velocity and shear stress were obtained...

Wave Forces on Models of Submerged Offshore Structures

The results of a model study of the farces caused by oscillatory waves on large rectangular tank-like submerged objects are presented. Three phases of the problem were examined: 1) description of the forces in terms of dimensionless parameters, 2) description of the effect of large wave heights which are of importance to the designer, and 3) the...

Effects of Slope Roughness on Wave Run-up on Composite Slopes

A comprehensive study of the wave run-up phenomena on single and composite slopes was conducted in order to determine the effects of slope roughness on regular and irregular wave run-up on composite sections, to determine the effects of slope roughness on the velocity distribution in the uprush zone, to investigate the energy loss in the uprush...

Scour of flat sand beaches due to wave action in front of sea walls

The erosion of sand beaches due to oscillatory water particle motion of non-breaking waves can be of importance, particularly where such a beach is fronted by a sea wall supported on spread foundation. Laboratory study was conducted with natural beach sand; waves were generated mechanically. Geometric variables included the inclination of sea...