Experimental determination of melting rates of ice moving in seawater

Abstract

Large, fresh-water ice blocks (0.5m X 1.25m X 5m) were towed in Monterey Bay at speeds in range from 0.7 to 1.2 knots, The objectives of the experiments included measurement of gross regression rates of ice surfaces, wake temperature, turbulent thermal boundary layer, ice interior temperature profile, and observation of shape changes over the melting period. The research was conducted over a period from October 1977 to January 1979. The measured regression rates at several points on the ice blocks were compared to theoretical predictions using a turbulent flow ice ablation model developed by Dr. Owen Griffin of the Naval Research Laboratory Griffin's model predicted a regression rate of 280ram/hr compared with the measured value of 26 0mm/hr at a selected point. Temperature profiles in the ice interior and ice-water boundary layer -were used in a one-dimensional energy balance across the melting interface. Ice ripples were observed on all ice block tests. The ripples are important for both heat transfer and drag considerations. The wavelengths of the ripples were measured and the average wavelength determined. The measured average wavelength was 6.1 inches compared to the theoretical average predicted by Tatinclaux and Kennedy of 5.8 inches for a selected experiment.