An approximate formula for calculating water depth of uniform flow in circular cross section

【Objective】 For present shortcoming of water depth of uniform flow in circular section,which is great calculating error and small application scope,this paper desired to get a new approximate formula.【Method】 Through mathematic-exchange from the equation of uniform flow in circular section,this paper got expression of non-dimensional parameter k,moreover used principle of the best approximation to do optimization and approximation to k and non-dimensional water depth x,an approximate formula for calculating water depth of uniform flow in circular section was gained.【Result】 Error analysis and application expresses that in the practical area of engineering,the maximum error of this formula was not greater than 0.9 percent.【Conclusion】 Comparing with the previous formulas,this formula has higher calculating precision and can be widely used and satisfy the engineering requirement.