Contribution of Viscous Forces to Avalanche Dynamics
Contribution of Viscous Forces to Avalanche Dynamics
复制标题
粘性力对雪崩动力学的贡献
作者：
K. Nishimura;N. Maeno
小型雪崩系统是在低温实验室和雪地中建造的，并观察了每种情况下流动雪的行为。确定了单个雪粒的速度分布，这意味着对于许多雪崩，需要考虑粘性力，这在以前的雪崩运动的数值模拟中被忽略了。用改进的Stormer型粘度计测量了流态化雪的运动粘度系数。将流态化积雪的干摩擦值和运动粘性系数代入雪崩运动方程，对石艾达尼地区的自然事件进行了数值模拟。考虑到粘性阻力因素，得出雪崩系统中雪的湍流阻力的大小可能比以前使用的数值要小得多的结论。
Mini-avalanche systems were constructed both in a low-temperature laboratory and in a snowfield, and the behaviour of the flowing snow was observed in each case. Velocity profiles for the individual snow particles were determined and these implied that a viscous force, which has been neglected in most previous numerical simulations of snow-avalanche motion, needs to be taken into account for many avalanches. Kinematic viscosity coefficients for the fluidized snow were also measured using a modified Stormer-type viscometer. Substituting the dry-friction value and the kinematic viscosity coefficient for fluidized snow into the equation for avalanche motion, numerical simulation of natural events was achieved for the Shiai-dani region. Taking viscous resistance factors into account led to the conclusion that the magnitude of turbulent resistance of snow in avalanche systems is probably much smaller than that represented by the values previously in use.