Unsteady Flow HEC-RAS Model Troubleshooting

Chapter 6 Additional Issues and Tips

Additional Issues and Tips

6.1 Other Issues

1. If a drop structure is present in the HEC-RAS model, the best way to represent this is with an

inline structure.

2. Lateral and inline structure stability factors can improve model stability. To improve model

3.

4. If the model crashes at the beginning of a simulation, check initial conditions such as

discharge values, storage area elevations, and downstream boundary conditions. If the model

model stability locations.

5.

elevation to match initial model conditions.

6.2 Other Tips

1.

the model to fail in its computations.

2.

model. Perhaps one of the structures is causing the model to fail. If the model suddenly runs

after removing the structures, then place the structures back in, one at a time, to see which

3.

could be occurring, which often causes model instability.

4. Use the Modified Puls Routing

5. Use the Variable Time Step option where the HEC-RAS computational engine dynamically

recomputes the required time step during the simulation based upon the Courant number