CFD Simulation On A Circular Cylinder With Barnacle Attachment

Today,various ocean developments have been carried out,including ocean renewable energy,ocean space utilization by a floating body and so on.In the ocean developments many problems have to be solved,one of which is the influence of biofouling caused by marine organisms.Because of the adhering organisms on the structure surface,the fluid force on the structure may become larger than expected.Further,biofouling can accelerate the deterioration of the structure.In this study,we focus on “barnacle” which has particularly strong adhesion among the adherent organisms.A circular cylinder,which is often found in the ocean structures and cables,is chosen for the study.The main purpose of the study is to answer the question of "How to predict the hydrodynamic forces of a circular cylinder with barnacle attachment on the surface".In this study numerical simulation is carried out to clarify the hydrodynamic influences of the attached barnacles on a circular cylinder.High Reynolds number cases are considered.It is shown that the drag coefficient predicted by the 3D numerical simulation is much lower than the experimental data(Onishi,2017).This phenomenon has been checked in this study and it is found the under prediction of the drag coefficient is due to the insufficient mesh resolution.Therefore,in the present study 2D simulation is carried out by using sufficient mesh resolution to study the biofouling effect of a circular cylinder.Numerical simulations on a bare circular cylinder and a circular cylinder with barnacle models are performed.The bare cylinder simulations are validated by using previous studies.The effect of barnacle density on the drag coefficient is discussed by using the numerical results.