These situations include mixed flow regime calculations (i.e. The momentum equation may be used in situations where the water surface profile is rapidly varied. Energy losses are evaluated by friction (Manning’s equation) and contraction/expansion (coefficient multiplied by the change in velocity head). The basic computational procedure is based on the solution of the one-dimensional energy equation. The steady flow component is capable of modeling subcritical, supercritical, and mixed flow regimes water surface profiles. The system can handle a full network of channels, a dendritic system, or a single river reach. This component of the modeling system is intended for calculating water surface profiles for steady gradually varied flow. The sediment transport component is under development at this time. Currently the steady and unsteady flow components of HEC-RAS are fully implemented for use. Tabulation and Graphical Displays of Input and Output Data The interface provides for the following functions: The main focus in the design of the interface was to make it easy to use the software, while still maintaining a high level of efficiency for the user. The user interacts with HEC-RAS through a graphical user interface (GUI). The following is a description of the major capabilities of HEC-RAS. HEC-RAS is designed to perform one-dimensional hydraulic calculations for a full network of natural and constructed channels. Please see the d istribution policy for more details. Downloading this software indicates full acceptance of your responsibility in the use of this program. See the software vendor list to locate organizations that provide the program, documentation, and support services for a fee. HEC will not provide user assistance or support for this software to non-Corps users.

Use is not restricted and individuals outside of the Corps of Engineers may use the program without charge. However, software developed at the Hydrologic Engineering Center is made available to the public whenever appropriate. Note: các bạn sinh viên có thể download phần mềm về và đăng ký các đè tài nghiên cứu khoa học dựa trên HEC-RAS

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