The system design for calibrating acoustic Doppler current meter in the laboratory

Abstract

The Acoustic Doppler Current meter is a most commonly device for the velocity measurement of the seawater in the ocean. We had designed an equipment to calibrate the Acoustic Doppler Current meter in the laboratory, which is mainly composed of a vertical circulating water tank and a system of Laser Doppler Velocimetry. The vertical circulating water tank is the key device of the calibration equipment. The optimization of flow field is carried out by the software, CFD. The optimization of structure intensity, modal analysis and low noise is carried out by the software, ANSYS. We had also used the propeller map to design the power section of the water tank. Through the comparison of the velocity of the flow between Acoustic Doppler Current meter and LDV at the same position in the working section of the water tank, the former can be calibrated, because the wavelength of optics is much less than that of acoustics in the water. After the experimental test, we found that when the fluid flows in the vertical circulating water tank, there exists no resonance phenomenon and the velocity of the flow in the working section is approximately proportional to the rotation speed of the propeller.