Two Dimensional flow

[Van PD Tri]

Hi to all,

HEC-RAS so far has been used to model one dimensional flow (i.e. the flow follows one direction; says from north to south). However, I face the trouble that in my river system, the cross-channel (i.e. the channel links two mains river) does not have only one flow direction. During the low flow, water runs from two rivers into the cross-channel therefore in simplicicty, at the middle of the cross-channel water level keeps rising up but the velocity is somehow equal to 0.

Have you ever tried to model this type of river system? Can you give me a clue on what document I should search for help?

Best regards,

Tri Van

[MattZ]

HEC-RAS can model flow reversals within the 1-D realm. For example, an unsteady flow model can take into account water moving downstream during low flows and then water moving upstream when a backwater conditions occurs in the receiving stream. I have also successfully modeled a channel with a high point in the middle and water flowing in opposite directions.

For a true 2-D model, where you want to take into account water laterally and longitudinally, you will have to employ a different software program.

[Van PD Tri]

Thanks for your reply.

I wonder if we can use steady flow regime to calculate the discussed issue?

Best regards,

Tri Van

[Van PD Tri]

I also wondering if we can consider different calculation regime for different reaches in HEC-RAS? Says, the two main river are calculated under sub-critical regime and the cross channel is calculated under the mixed flow regime?

Best regards,

Tri Van