Analytical Study Of The Hydrodynamic Characteristics For CALM Buoy With A Skirt

As a key element of CALM buoy, the skirt can effectively improve the system of add mass and provide additional hydrodynamic damping, In return significantly reduce the buoy heave and pitch motion and rolling motion. Meanwhile, in a rapidly changing marine environments, the skirt can protect the buoy from damage to ensure normal working conditions. So that CALM buoy increase the security while significantly reducing construction costs.The advantages of eigenfunction expansion method is the absence of boundary integral method handle problems of irregular frequency waves generated by interactions with the floating body.This article uses the eigenfunction expansion method to establish computational models of CALM buoy with dense and permeable skirt. The flow field is divided into four sub-regions of internal floats, floats outside, the upper and the lower. Use three-dimensional separation of variables column coordinates to obtain the complete the expression by freedom water surface and seabed conditions. Then get the velocity potential in each sub-domain of undetermined coefficients and wave forces suffered with skirt buoys and hydrodynamic coefficients by matching boundary. Solving the equations of motion to get buoys swaying motion response. Make buoys radius tends to zero, that is underwater heave plate. Make skirt radius equal to the radius of the buoy get a floating vertical cylinder. Buoy radius tends to zero and make a skirt thickness is large enough, that is underwater cylindrical caseUse Matlab programming, and compare the results with AQWA to verify the accuracy.Analyze the skirt radius and the thickness. When solving the buoys motion response considering the effect of heave and pitch viscous damping.This paper analyzes the impact of the skirt radius, thickness and other factors on radiation and diffraction.Obtained a series of conclusions.Finally, excluding the apron under the influence of the thickness of the conditions apron opening rate to buoys wave power.