Experimental investigation and analysis of hydrodynamic characteristics of a net panel oscillating in water

Abstract To investigate the behaviour and hydrodynamic characteristics of supple nets in a wave, experiments of forced oscillation were conducted in a tank with square net panels. The four corners of the net panel were fixed to the oscillation device with a specific pretension. The hydrodynamic loads acting on the corners of the netting were measured. To simulate the experiments, a numerical model based on dynamic finite element analysis was constructed. Comparing the amplitude and phase of measured loads with the calculated results, the drag coefficient C d and inertia coefficient C m were determined by interpolation and iteration. The effects of various parameters on C d and C m were investigated. The results show that: (1) drag force is dominant at low frequency, whereas the contribution of inertia force increases with an increase of the Keulegan–Carpenter number or frequency; (2) with increasing frequency, both C d and C m show a decreasing trend, and the trend of C d against the Reynolds number is similar to that in steady flow; (3) increasing oscillation amplitude makes C d decrease, but it has no significant effect on C m ; (4) solidity generally has a positive effect on C d and C m .