FLOW & NOISE

This article presents an experimental study of flow around a surface-piercing cylinder at Froude number 0.87 to 1.73. The bow wave height, wake pattern, air ventilation, and noise generated have been investigated extensively for different cylinders design such as circular and elliptical cylinders. An image processing technique is applied to visualize the air entrainment and calculate the air volume fraction underwater. The result reveals that the wake region and the bow wave increases significantly as the Froude number increase, accompanied by an air cavity and vortex shedding region behind the circular cylinder, while there was less increment in the bow wave height and wake region as well as there was no air cavity for the case of an elliptical cylinder.

In this study, we present the Laser Doppler Velocimetry (LDV) measurements in the flow past three-dimensional hydrofoils inclined at an angle of 10◦ with respect to the free-stream velocity. The swirling strength of the tip vortices are qualitatively evident from the measurements of z velocity component field for all the hydrofoils, at various aspect ratios and Reynolds numbers. It is observed that the magnitude of normalized axial velocity deficit and normalized turbulent kinetic energy are dependent on the type of hydrofoil, their aspect ratio and the Reynolds number.