Simultaneous Measurements of Flow and Termperature Fields Near Melting Ice-Water Interface

We present a laboratory setup and associate measurements on the melting of a vertical ice face under the influence of a subglacial 2D (line) buoyant jet discharge. This experimental configuration is relevant to sea-terminating glaciers in Greenland whose mass loss has been recognized as a major contributor to sea-level rise and climate change. Heat flux measurements near the melting ice-water interface are needed to link the melt rate and the properties of the 2D jet together. The technical challenge lies in obtaining resolved spatial-temporal flow and temperature data near the ice face. We have tackled this challenge by combining the techniques of two-color LIF and planar PIV inside a 1m-by-1m-by-0.3m water tank with an overflow weir for steady flow control. We report heat flux and melt rate data at three different heights of a 0.8m-tall ice block. Previous applications of the two-color LIF technique were limited to small experimental setups e.g. microchannels or cross-sections of size less than 10cm. This is mostly because of laser power atteunation through dyed water and the subsequent reduction in signal-to-noise (SNR) ratio. We demonstrate here that the technique can be sucessfully applied in experimental setups up to 1m by judiciously choosing the laser power, optics, individual dye concentrations, and the concentration ratio of the two dyes. We also show that the chosen fluorescent dyes survive freezing-melting cycles and both remain potent, enabling us to measure the temperature fields of melt water.