No abstract

The aim of this study was to clarify the frazil slush generation mechanism on ice-covered rivers. This study developed a frazil slush generation calculation model which targeted skim ice, frazil ice, snow fall and anchor ice. The input values for this model were air temperature, wind velocity, sunshine duration, snow-fall depth, water depth of river, flow velocity of river and latitude. We carried out field observations at a location where frazil slush floats on the water surface, recording data with a camera. It was shown that the calculation model generated by this study can reproduce the frazil slush generation of the real river. It was also found that rising air temperature, an increase in frazil slush thickness and falling upstream water levels are important factors in predicting the occurrence of water intake blockage caused by frazil slush.

No abstract

In this paper, Frazil slush variation mechanism and a method of frazil slush variation estimation on ice-covered river are studied. This study did develop a frazil slush generation, transport and accumulation calculation model. The continuous input values of this model are air temperature, wind velocity, sunshine duration, snowfall depth and water level. We carried out field observation of frazil slush accumulation using the ADCP and the SWIP. It was shown that the calculation model built by this study can reproduce the frazil slush variation of the real river. The increase of frazil slush transport, the increase of frazil slush generation and the upstream frazil slush accumulation volume are important values when considering frazil slush blockage of water intakes.

Anchor ice is a phenomenon to accumulate of frazil ice on the river bed. This is formed due to the super cooling and a shallow, turbulent section of the river. But, it is a poorly understood and little studied topic. Our study focuses on elucidate the material cycle of freezing river. We had a continuous observation of air temperature, water temperature, water level and all day shooting of anchor ice formation using IP-camera during an anchor ice presence-absence cycles. From the result, we found the critical element of anchor ice presence-absence is under super cooling condition. We attempted to analyze two-dimensional flow calculation and spatial distribution of photo image analysis of an anchor ice. As a result, we found spatial distribution of anchor ice is proportional to the Froude number. We analyzed the contained materials of an anchor ice. As a result, a lot of algae (Hydrurus foetidus and diatoms) existed in the anchor ice. We showed the possibility that anchor ice affected the material cycle of freezing river.