颗粒流动量方程中固相压力项的疑惑

[xzlzju]

在fluent手册介绍固相压力处写到“The solids pressure is composed of a kinetic term and a second term due to particle collisions”，即固相压力包含动力及碰撞两个部分，不包含摩擦压力。但是在介绍摩擦压力时，又写到“The frictional stress is added to the stress predicted by the kinetic theory when the solids volume fraction exceeds a critical value.”所以，当固相体积分数超过临界摩擦体积分数时，固相动量方程中的固相压力项是否包括摩擦压力呢？