Arash Niroomandi

Coastal and Hydraulic Engineer

I am a PhD student at Old Dominion University majoring in Coastal Engineering. My interests include a wide range of hydraulic and hydrodynamic phenomena. I am especially interested in numerical modeling of water and related environmental issues such as transient flow in pipe and river networks, sediment transport, two-phase flow, and coastal hydrodynamics. My resume provides additional information about my background, previous work and academic experience, but please contact me directly if you would like to discuss specific questions or opportunities.

• Address135 Kaufman Hall Civil & Environmental Engineering Department Old Dominion University Norfolk, VA 23529
• Emailaniro001@odu.edu

• All
• Pipe Network
• River Network

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  Small Pipe Network 3D

  Pipe Network Download
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  Small Pipe Network 2D

  Pipe Network Download
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  Closed loop Network

  Pipe Network Download
• 

  Three-pipe Junction

  Pipe Network Download
• 

  Three River Network

  River Network Download

Modeling of transient flow in closed conduits

The aim of pipe network analysis is to compute equilibrium distribution of head and flow for users at different operating conditions. This process was done in early systems under steady flow conditions which mostly led to poor estimation of flow and head in the system. However, after realizing the concept of transient flow in closed conduits, analysis of pipe network has become far more complicated. Transients in pipe network mostly occurs due to sudden change in water demands and water usage, starting or stopping the pumps or mechanical failure of devices which cause undesirable damages to water distribution systems. Due to the importance of this phenomenon in this research we proposed a one dimensional model to simulate transient flow in pipe network. In order to do so, Time Splitting Projection Method (TSPM) and Double Sweep method (DSM) have been implemented. Firstly, TSPM is utilized to solve the continuity and momentum equations in a single pipe. TSPM is a semi implicit method which splits governing equations of transient flow into a series of equations readily and therefore simplifies the solution of these equations in a single pipeline. Then DSM is implemented to simulate flow in pipe network. In this method, values of the unknowns in all grid points of a pipe can be related to the first and last grid points. Therefore, number of unknowns and consequently execution time is reduced significantly.



Modeling of transient flow in open conduits

Unsteady flow occurs in open channels when the discharge or depth or both vary with time at a section. Flood in the rivers, streams and lakes caused by snow-melt, opening or closing of control gates and waves in a river or a reservoir created by a dam break are some examples of transient condition that can happen intentionally or accidentally. This phenomenon has been responsible for numerous losses. Thus, giving careful attention to this problem is of great importance. Although hydrodynamic phenomena in rivers and reservoirs are physically three dimensional, by making some assumptions it is possible to consider that the flow is one dimensional. The governing equations of unsteady flow in open channels in one-dimensional form are Saint-Venant equations. For solving these equations various methods including analytical, numerical, graphical and approximate models have been presented. With respect to high efficiency of one-dimensional models in riverine studies, in this research we proposed a one-dimensional model to solve the equations of open channel flow. Time Splitting Projection Method (TSPM) is applied to solve the governing equations of unsteady flow in open channel using explicit and implicit techniques. For modeling flow in river network Double Sweep Method (DSM) is implemented. The proposed model is validated by comparing the numerical results with a benchmark analytical example (dam break problem) and also with the results of Mike 11 commercial software.