The design lowest navigable water level is a primary index to the channel grade division.But differ- ent method can get different calculated result,and that even brings contradiction to decide the navigation grade.In ...The design lowest navigable water level is a primary index to the channel grade division.But differ- ent method can get different calculated result,and that even brings contradiction to decide the navigation grade.In this paper the differences between guaranteed rate method and guaranteed rate-frequency method on the fundamental concept of guaranteed rate and the calculated result are carried out.According to the theoreti- cal expression forms of the two methods,the reason leading to the difference is an...展开更多
A model has been constructed to study water flow in a single clay crack, and a new concept of the critical rise rate of water level in the crack has been put forward. When the water level rises faster than this critic...A model has been constructed to study water flow in a single clay crack, and a new concept of the critical rise rate of water level in the crack has been put forward. When the water level rises faster than this critical rate, the flow in a crack will increase, and vice versa. The flow in a crack is not in proportion to the water level. The maximium water flow in clay is 30-40 times smaller than that in a rock fissure under the same condition. In the process of water discharge, the flow in a crack will lessen gradually, and the crack will grow narrower by 3.0-4.0cm, with its depth reducing by over 50%.展开更多
受电站下泄非恒定流影响,溪洛渡下游30 km区域通航水流条件复杂,威胁船舶通航安全。通过原型观测,对非恒定流传播规律及其主要影响因素进行研究。结果表明,各码头的水位变化与泄流变化趋势一致,传播过程中沿程坦化现象明显,传播速度快,...受电站下泄非恒定流影响,溪洛渡下游30 km区域通航水流条件复杂,威胁船舶通航安全。通过原型观测,对非恒定流传播规律及其主要影响因素进行研究。结果表明,各码头的水位变化与泄流变化趋势一致,传播过程中沿程坦化现象明显,传播速度快,大河湾—顺河段的平均波速为11.2 m s,汛期大河湾码头水位变幅及变率高达4.38 m、1.21 m h。溪洛渡坝下河道非恒定流特性与下泄流量变幅、变化时长及向家坝库水位有关,其中对流量变幅的响应最大。泄流增加(减少)时,电站下泄流量变幅越大,变化时长越短,向家坝库水位越高(低),非恒定流传播速度就越快,码头水位变幅及水位变化率就越大。展开更多
基金Supported by the National Key Basic Resarch and Development Plan (Grant 2003CB415200)
文摘The design lowest navigable water level is a primary index to the channel grade division.But differ- ent method can get different calculated result,and that even brings contradiction to decide the navigation grade.In this paper the differences between guaranteed rate method and guaranteed rate-frequency method on the fundamental concept of guaranteed rate and the calculated result are carried out.According to the theoreti- cal expression forms of the two methods,the reason leading to the difference is an...
文摘A model has been constructed to study water flow in a single clay crack, and a new concept of the critical rise rate of water level in the crack has been put forward. When the water level rises faster than this critical rate, the flow in a crack will increase, and vice versa. The flow in a crack is not in proportion to the water level. The maximium water flow in clay is 30-40 times smaller than that in a rock fissure under the same condition. In the process of water discharge, the flow in a crack will lessen gradually, and the crack will grow narrower by 3.0-4.0cm, with its depth reducing by over 50%.
文摘受电站下泄非恒定流影响,溪洛渡下游30 km区域通航水流条件复杂,威胁船舶通航安全。通过原型观测,对非恒定流传播规律及其主要影响因素进行研究。结果表明,各码头的水位变化与泄流变化趋势一致,传播过程中沿程坦化现象明显,传播速度快,大河湾—顺河段的平均波速为11.2 m s,汛期大河湾码头水位变幅及变率高达4.38 m、1.21 m h。溪洛渡坝下河道非恒定流特性与下泄流量变幅、变化时长及向家坝库水位有关,其中对流量变幅的响应最大。泄流增加(减少)时,电站下泄流量变幅越大,变化时长越短,向家坝库水位越高(低),非恒定流传播速度就越快,码头水位变幅及水位变化率就越大。
