溢流坝水流的有限元—过渡线联合解法

本文介绍一种确定过坝势流的流量系数和自由表面的新方法。这一方法的主要特点是引进了一条三次型过渡线,它构成包括临界点在内的自由边界的一部分。采用过渡线后,寻找临界点的确切位置这一艰难工作就不必要了,而且通常在临界点处的计算不稳定性也消除了。并为最大流量Q的确定提供了一些理论依据。Q值的调整规律也给出了。过渡线方法的收敛情况是十分令人满意的。而且初始数据不必十分精确,而计算时间比其它方法要少得多,并且计算结果与实验数据吻合得很好。

JOINT USE OF THE FEM AND TRANSITION CUBIC FOR ANALYSIS OF FLOw OVER A SPILLWAY CREST

In this paper a new method is presented for the determination of the discharge coefficient and the profile of the free surface of a potential flow over a spillway crest. This method is characterized by introducing a transition cubic, which forms a part of the free boundary containing the critical point as its internal one. The use of the TC gets rid of the laborious work of looking for the exact location of the critical point and eliminates the computational instability which occurs frequently at the critcal point. The present study provides a sound theoretical basis for the determination of the maximum discharge Q and gives a rule for adjustment of the value of Q. The convergence of TC method is quite satisfactory in that the initial data need not be very accurate. Moreover, the computing time required by this method is much shorter than that by other methods. The calculated values conform to the experimental data fairly well.