Dye-Vector Flow Visualization—Cooling Water Model

An extensive hydraulic scale model (densimetric Froude law) of the intake and discharge flows of the cooling water system of an ocean coast power plant with coastal currents, made use of flow visualization techniques to obtain details of patterns near the discharge and intake. This was important to develop insights to the characteristics of the mixing and induced bottom flows. One technique was to drop dye crystals to the bottom, and photograph (in color) the growth of the dye vectors. This was so useful that a thorough quantitative study was made of the growth rate of these vectors, U_d, relating the growth rate to the friction velocity, U*. The results were interpreted using boundary layer theory and numerical and physical model studies of low Reynolds number flow around objects. For a range of values of U* of practical importance in hydraulic model studies over hydraulic smooth bottoms, a linear relationship between U* and U_d was established. This appears to be a new quantitative technique.