Wave flume

About: Wave flume is a research topic. Over the lifetime, 1627 publications have been published within this topic receiving 23335 citations.

Laboratory investigations on wave attenuation characteristics of Rhizophora Mucronata poir using physical models with bottom friction

Abstract: Species specific hydrodynamic characterization is essential for assessing the suitability of various types of mangroves in coastal protection as the dissipation of wave energy within the mangroves is governed primarily by various aspects which are specific to the species to which they belong. In the present study a specific mangrove species was selected and its wave attenuation characteristics were studied with the help of scaled physical models under controlled wave and vegetation conditions in a laboratory wave flume. The plant was initially identified as Rhizophora Mucronata and the scaled models prepared had the same biomechanical properties as that of the parent plant. Effect of root soil was incorporated in scaled models as bottom friction. Wave heights were measured after the forest models to evaluate the wave attenuation. It was found that wave heights were following the exponential decay equation of Kobayashi et al. (1993) except for the cases which have incorporated bottom friction. For such cases exponential decay equation was modified by incorporating a new parameter ‘d/D50’. Drag coefficients (CD), characteristic of the species were also determined without incorporating and with incorporating the effect of bottom friction of root soil. It is seen that drag coefficients are following an inverse relation with non-dimensional numbers (Re and KC). Empirical relations were developed between CD and a modified Keulegan Carpenter number (modified considering mangrove root submergence and mean particle size) for predicting the drag coefficients specific to Rhizophora Mucronata species for a variety of wave and water level conditions.

The effect of currents on the mass transport of progressive water waves

Abstract: The pickup velocity of water offshore of the breaking zone is dominated by the particle orbital velocities of the waves near the bed, whereas the rate of transportation of fine material is dominated by mass-transport effects. The effects of even very small currents on the mass transport of waves could be very large. Results are given of some experimental work on waves with very small superimposed collinear currents. The mass-transport velocities and currents cannot be added algebraically. A theory is developed which is based on the algebraic addition of the particle velocities in the boundary layer at the bed, assuming laminar motion. The agreement between theory and experiment is found to be quite good for small wave heights; it is better for larger wave heights with shorter wave periods than with longer wave periods.