Parameter identification methods of hydraulic models for the study of current water in open channels

Abstract

Abstract Both adequacy of the mathematical model and accuracy of the initial data define the adequacy of numerical results of the real process. Being the phenomenological model, the model of current water based on one-dimensional Saint-Venant equations has the parameters which cannot be determined within the scope of one-dimensional model. The most important such parameter is, for example, the Chezy coefficient (coefficient of roughness) or the wind stress coefficient. The main difficulty to use the one-dimensional model is that the parameters are hardly measured. In this paper we suggest the numerical method of identification of such hydraulic parameters as the coefficient of roughness, the wind stress coefficient and so on, given the actual measurement data of free surface level or of flow depth. We assume that the flows is gradually varies and describes by the Saint-Venant equations. Also we assume that the identification parameters do not vary on the whole length of the channel. The developed methods are based on the Bellman method of sensitivity and on the modified Newton method which are applied for minimization of the functional of mean square deviation of the calculated parameters of the flow from the measurement data. The examples of recovery of hydraulic parameters, in particular, for real objects are considered.