粘性流

Because of the viscosity of fluid and non-existence of velocity potential, the symmetry of mass matrix, stiffness matrix and the coefficient matrix of the first order of system no longer exists, so the modal analysis of system becomes very complicated.

由于流体粘性的影响，流场有旋，没有速度势，所以系统质量阵、刚度阵以及一阶项的系数矩阵的对称性被破坏，从而使得系统的模态分析变得很复杂。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。