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  • 1.  Modeling unsteady flows in large scale rivers with secondary flows

    Posted 01-15-2023 11:04 AM
    One of the most interesting studies in Hydraulic Engineering is modeling unsteady flows in complex flow conditions. In unsteady flow conditions, the main channel may not be enough to carry the released discharge or flood. Thus, floodplains can be constructed with different structures and roughnesses as per required to minimize the effect of floods. In this condition, the secondary flow term is one of the key parameters to be estimated or simulated. what is secondary flow?  what is the most method to estimate secondary flows? can we observe the secondary flows in the large rivers practically? any current findings about secondary flows except SKM? Any comments or suggestions are welcome!

    '' With Regards''

    Ebissa, S.M. ASCE
    PhD Scholar in Hydraulic Engineering

    Ebissa Gadissa S.M.ASCE
    PhD Scholar
    Addis Ababa

  • 2.  RE: Modeling unsteady flows in large scale rivers with secondary flows

    Posted 01-17-2023 02:49 PM

    Without going into the specifics, here are the links to two publications: Turbulent Flow Structure in Large Alluvial Rivers; and Seabed Roughness. If you find them interesting but have difficulty in accessing them – write to me, I can forward you the author reprints. Hopefully they will help you answering or clarifying some of your queries – as well, lead you to other relevant references.

    Further, as you know:

    • Any shallow-water 2D numerical modeling (see Water Modeling) suite would simulate secondary flows, eddies or vortices (see Turbulence) – provided model resolution in both space (river bed and bank) and time is fine enough to resolve the secondaries. In addition to simulating primary or mean flows (see Common Sense Hydraulics) – the secondary flow dynamics will surface if 8 sources of modeling uncertainties (as outlined in Water Modeling) – are given proper attention to while developing the numerical model.

    • Such 2D modeling suite also allows one to include floodplain into the modeling domain (to simulate release and storage of flows during falling and rising river stages, respectively) – if the suite is equipped with flooding and drying capabilities (such capabilities prevent crashing of model simulations while water level rises and falls).


    Dr Dilip K Barua, PhD


  • 3.  RE: Modeling unsteady flows in large scale rivers with secondary flows

    Posted 01-19-2023 01:42 PM
    Edited by Tirza Austin 01-19-2023 01:42 PM
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