DEVELOPMENT OF AN OPTIMAL ARRAY OF SENSORS FOR THE RECONSTRUCTION OF A RIGID ROUGH SURFACE BASED ON SCATTERED ULTRASOUND

摘要

Traditional ways of measuring the properties of a flow, such as the velocity and depth of rivers, usually require leaving the sensors submerged underwater for long periods of time. This causes larger costs of maintenance and larger potential risks for the operators, which add to the already high cost of the equipment. Alternative techniques based on optics, microwave, or ultrasound, are able to estimate the flow conditions remotely, by measuring the velocity of particles observed right below the water surface, or by measuring the speed of the deformed water-air interface. The behavior of the surface is of large importance also for the exchange of gas, such as CO2, between the flow and the atmosphere. However, the dynamics of this interface are complex and still largely unknown, especially at the small centimetre scale which affect the scattering of light, microwave, and ultrasound, more strongly. As a result, the measurements obtained with these techniques are often unreliable over wide ranges of conditions.