광음향 변조효과를 이용한 유체의 방향 결정

Determination of Flow Direction by Using an Acousto-Optic Effect

The flow direction in a glass tube is measured by using a forward scatering dual beam laser Doppler velocimeter with an acousto-optic modulator. We can determine the flow direction by measuring the shifted Doppler frequency which is dependent on the order of modulation of the laser frequency shifting moves only the Doppler signal, enabling complete separation of the Pedestal and Doppler singal.