Experimental Study And Numerical Simulation On Growth And Decay Of Hydrostatic Ice-cover

In winter the formative Hydrostatic ice-cover is easy to cause fish frozen and reservoir hydraulic structures damage, based on the purpose of preventing and mitigating ice disaster, this paper do prototype observation experiment at different times for different water depths during ice period, steady stage seal, melting period in south lake pool of Tuoketuo county in Inner Mongolia in two winters of 2014-2015,2015-2016. According to the results of the experiment, analysis test data such as ice thickness, water temperature, ice temperature, combined with the temperature change to explain ice parameters change rule, and then sums up Hydrostatic ice-cover growing and melting evolution regularity and mechanism, and combining the thermodynamic basic equations, to establish mathematical model on growth and decay and water temperature coupling of Hydrostatic ice-cover, through the measured and simulated values compared to the model simulation results are analyzed. The following main achievements were obtained.(1) Growth and decay of ice cover was mainly affected by temperature, ice thickness was affected by air temperature at different time obviously during ice cover unstable change period and later melting period, change significantly within a day, ice thickness is mainly influenced by cumulative average daily negative temperature during stable growth period of the ice cover, and the air temperature at different times effect on the smaller. Within ice growth period, ice growth slope were different at different times, the higher air temperature within a day, the lower ice growth slope, the ice growth slope at 14 is lower than that at 8.(2) Water depth less impact on the evolution of the ice cower and more impact on the largest ice thickness and ice complete melting time, the deeper the water depth, the greater the ice thickness relative, ice melts to disappear the longer.(3) In the growth process of ice cover, water temperature are distributed in vertical inversion, air temperature have an effect on the layered structure of water, water surface temperature are greatly influenced by air temperature change, and deeply influenced by its relatively small, compared with 8 am and 14 pm, with the same depth, the water temperature on the high side at 14, and the overall water temperature distribution is uplift. In melting period, as air temperatures rise, the trend of water temperature uplift firstly slow, then quick, different layers of water temperature variation is larger, the variation of water temperature at 14 is more severe than that at 8.(4) In the process of growth and decay of the ice cover, the ice surface temperature affected by air temperature at different times significantly, followin the changes of air temperature fluctuation, when air temperature higher, the ice temperature is close to 0℃, the lower air temperature, the lower ice surface temperature.(5) Based on the thermodynamic theory, the model equations of water temperature and ice thickness changes were established. To solve the model of water temperature and growth and decay of ice cover coupling, and to simulate field water freezing and melting process, analyzing the simulation results were compared with the measured results, found that the water temperature, ice thickness simulation results wre consistent with the test results. This model in simulating static water freezing and melting have higher precision. The results are expected to provide theoretical foundation and reference basis when study the static water ice cover growing and melting process and water temperature under ice cover in time and space distribution.