说明：  由两平行平板组成的突扩通道，尺寸如图所示。流动为层流。入口流速均匀，入口温度均匀，通道壁温均匀。分子粘性、密度已知，求：通道中流体的速度分布、温度分布、密度分布及压力场。
(Formed by two parallel plates sudden expansion channel, size as shown. Flow is laminar flow. Uniform inlet velocity, inlet temperature uniformity, the channel wall temperature uniform. Molecular viscosity, density is known, find: channel fluid velocity distribution, temperature distribution, density and pressure field.)