closing equation meaning in English

闭方程

However , the forecast ability of the mathematical model is restricted since it is difficult to consist of the closed equations in a large amount of flow problems in hydraulic engineering the synthetic model , which combines the experimental and numerical simulation , is normally used for these complicated problems the results are satisfied in hydraulic engineering
但由于水利工程中相当数量要研究的水流过程还不能组成封闭的方程组，因而使得数学模型的预报能力受到限制。目前，在许多情况下，常采用模型试验和数值模拟相结合的复合模型方法解决复杂的工程问题，并能获得比较满意的结果。