Spurious Numerical Oscillations in the Preissmann Slot Method: Origin and Suppression

Malekpour, Ahmad; Karney, Bryan W.

doi:10.1061/(asce)hy.1943-7900.0001106

Cited by 28 publications

(50 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This may be due to the fact that, despite the application of slope limiter functions, the numerical method introduces an insufficient amount of numerical viscosity around sudden flow regime transitions, where an abrupt change occurs in the wave celerity. 51,52 The flow state discontinuity at x = 0 is correctly predicted, and no unphysical oscillations appear at this location. It must be noticed that the accuracy in the prediction of the flow state discontinuity depends on the goodness of the numerical estimate of the water pressure force exerted by the deck surface on the flow.…”

Section: D Test Cases With Analytical Solutionmentioning

confidence: 69%

“…However, very small spurious oscillations arise in the pressure head profiles of Tests 1 and 4 at the conduit‐filling bores. This may be due to the fact that, despite the application of slope limiter functions, the numerical method introduces an insufficient amount of numerical viscosity around sudden flow regime transitions, where an abrupt change occurs in the wave celerity . The flow state discontinuity at x = 0 is correctly predicted, and no unphysical oscillations appear at this location.…”

Section: Validation Of the Modelmentioning

confidence: 99%

See 1 more Smart Citation

Numerical treatment of a discontinuous top surface in 2D shallow water mixed flow modeling

Maranzoni

Mignosa

2017

Numerical Methods in Fluids

View full text Add to dashboard Cite

Summary This paper presents a numerical strategy based on shallow water equations (SWE) coupled with the 2D Preissmann slot model to handle a ceiling step discontinuity in finite volume schemes for mixed flow modeling. In practice, a typical situation would be a closed structure, such as a bridge or culvert, which induces a sudden vertical flow constriction and may even run partly or totally full in high flow conditions. In such case, both the inlet and outlet of the structure involve a discontinuity in the top elevation. This special singularity is topologically represented by inserting a fictitious cell between 2 adjacent computational cells characterized by sharply different ceiling elevation. The 2D SWE are solved by means of a well‐balanced quasi‐conservative Godunov‐type numerical scheme based on the Slope Limiter Centered (SLIC) scheme. The flow variables at each boundary of the fictitious cell are reconstructed by adopting the cross‐sectional shape of the adjoining cell. Accordingly, the dynamic effect of the structure deck on the flow is suitably modeled, and the C‐property for a stationary solution is rigorously satisfied, even when the closed structure is partially full. The capability of the numerical scheme is verified by comparison with both novel analytical solutions of 1D Riemann problems with a ceiling step discontinuity and experimental data of steady and unsteady mixed flows available in literature. Finally, a real‐scale application to a multiple arch bridge is presented. The results show that the method is robust and effective in predicting the 2D features induced by a crossing structure on the flow dynamics.

show abstract

Section: D Test Cases With Analytical Solutionmentioning

confidence: 69%

Section: Validation Of the Modelmentioning

confidence: 99%

Numerical treatment of a discontinuous top surface in 2D shallow water mixed flow modeling

Maranzoni

Mignosa

2017

Numerical Methods in Fluids

View full text Add to dashboard Cite

show abstract

“…1D unsteady open channel flow can be described by Saint-Venant equations. According to the Preissmann slot method [17][18][19][20][21], pressurized flow can also be calculated through the Saint-Venant equations by adding a conceptual narrow slot on the top of a closed pipe. The Preissmann slot approach assumes that the narrow slot is open to the atmosphere, so the shallow water equations can be applied including this slot.…”

Section: Saint-venant Equationsmentioning

confidence: 99%

Experimental and Numerical Investigation of River Closure Project

Lin

Jin

et al. 2020

Water

View full text Add to dashboard Cite

The success or failure of river closure is directly related to the construction period and project benefit. Therefore, it is very necessary to study the river closure by an appropriate method. In this paper, a 1D–2D coupled river closure model is established to optimize the closure flow rate, closure period, and layout of a real closure project. The 1D transition model between open channel flow and pressurized flow is established by a finite volume scheme. For the 2D model, 2D shallow water equations are solved using an unstructured finite volume scheme. The 1D model and 2D model are coupled by considering the mass and momentum conservation. To validate the model, a physical experiment of a real river closure project is set up according to the gravity similarity criterion with a scale of 1:80. Then, the experimental data obtained by the calibrated physical experiment is compared with the numerical results. Good agreements are achieved in terms of surface elevation, velocity, and flow rate. Finally, the real river closure project is further investigated by the model. The layout, closure flow rate and closure period of this project is analyzed and optimized. The original design of the berm is more suitable to discharge the flow. Moreover, the first stage cofferdam should be removed to floor elevation upstream and downstream of the dam. The river closure flow rate should not exceed 2380 m3/s.

show abstract

“…The mass exchange, heat transfer and temperature change between water and air in pipe are neglected. Meanwhile, in order to calculate the unsteady mixed water flow in pipe, the free surface flows, pressurized flows and free-surface-pressurized flows are uniformly expressed by the conservative form of Saint-Venant equations with the concept of the Preissmann slot [27]. Thus, the water and air are described by Saint-Venant equations [Equations (1a) and (1b)] and VRNS equations [Equations (2a) and (2b)], respectively.…”

Section: Numerical Modelmentioning

confidence: 99%

Experimental and Numerical Study on Water Filling and Air Expelling Process in a Pipe with Multiple Air Valves under Water Slow Filling Condition

Liu

Zhang

et al. 2019

Water

View full text Add to dashboard Cite

This paper investigates the physical processes involved in the water filling and air expelling process of a pipe with multiple air valves under water slow filling condition, and develops a fully coupledwater–air two-phase stratified numerical model for simulating the process. In this model, the Saint-Venant equations and the Vertical Average Navier–Stokes equations (VANS) are respectively applied to describe the water and air in pipe, and the air valve model is introduced into the VANS equations of air as the source term. The finite-volume method and implicit dual time-stepping method (IDTS) with two-order accuracy are simultaneously used to solve this numerical model to realize the full coupling between water and air movement. Then, the model is validated by using the experimental data of the pressure evolution in pipe and the air velocity evolution of air valves, which respectively characterize the water filling and air expelling process. The results show that the model performs well in capturing the physical processes, and a reasonable agreement is obtained between numerical and experimental results. This agreement demonstrates that the proposed model in this paper offers a practical method for simulating water filling and air expelling process in a pipe with multiple air valves under water slow filling condition.

show abstract

Spurious Numerical Oscillations in the Preissmann Slot Method: Origin and Suppression

Cited by 28 publications

References 15 publications

Numerical treatment of a discontinuous top surface in 2D shallow water mixed flow modeling

Numerical treatment of a discontinuous top surface in 2D shallow water mixed flow modeling

Experimental and Numerical Investigation of River Closure Project

Experimental and Numerical Study on Water Filling and Air Expelling Process in a Pipe with Multiple Air Valves under Water Slow Filling Condition

Contact Info

Product

Resources

About