A QUASI-TWO-DIMENSIONAL STREAM TUBE MODEL FOR SIMULATING FLOW IN ALLUVIAL RIVERS

I. INTRODUCTIONIt is necessary, sometimes, to predict river bed deformahon during the alanning and design stages of a hydraulic project. As the nuvial process is quite complicated, the I --Dmathematical models currently in use can not satisfy the various needs in hydraulic engineering. Particularly in engineering practice, there is a strong desire of knowing the hydraulicconditions and river bed deformation in details. Some two dimensional models as well asqusi--two--dissensional models …

A QUASI-TWO-DIMENSIONAL STREAM TUBE MODEL FOR SIMULATING FLOW IN ALLUVIAL RIVERS

In this paper a mathematical model of velocity distribution of depth average is presented. Based on field data measured from natural rivers, an empirical formula for computing the variation of roughness coefficient along the transversal direction is developed. Applying the basic concepts of stream tube method, the finite difference method is used for solving the equation of motion and a quasi-two-dimensional stream tube model is estab lished. This model has the advantage to avoid the arbitrariness in plotting the stream tube diagram of plane flow, and also save the CPU time and memery capacity of the computer. The model has been verified against field data obtained in two typical river reaches in the Middle Yangtze River.