On some explicit local time stepping finite volume schemes for CFD

Jeanmasson, G.; Mary, Ivan; Mieussens, Luc

doi:10.1016/j.jcp.2019.07.017

Cited by 10 publications

(4 citation statements)

References 31 publications

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“…The unsteady Reynolds-averaged Navier–Stokes (URANS) equations were numerically solved. Pseudo-transient simulations based on a local time stepping (LTS) numerical scheme [ 26 ] were performed to reduce the computational burden. In this approach the simulation is forced toward a steady state condition similarly to the Reynolds-averaged Navier–Stokes (RANS) approach, but with no need to remove the time derivative in the Navier–Stokes equations, therefore improving stability especially for complex geometries.…”

Section: Methodsmentioning

confidence: 99%

Investigation of the Wind-Induced Airflow Pattern Near the Thies LPM Precipitation Gauge

Chinchella

Cauteruccio

Stagnaro

et al. 2021

Sensors

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The airflow velocity pattern generated by a widely used non-catching precipitation gauge (the Thies laser precipitation monitor or LPM) when immersed in a wind field is investigated using computational fluid dynamics (CFD). The simulation numerically solves the unsteady Reynolds-averaged Navier–Stokes (URANS) equations and the setup is validated against dedicated wind tunnel measurements. The adopted k-ω shear stress transport (SST) turbulence model closely reproduces the flow pattern generated by the complex, non-axisymmetric outer geometry of the instrument. The airflow pattern near the measuring area varies with the wind direction, the most intense recirculating flow and turbulence being observed when the wind blows from the back of the instrument. Quantitative parameters are used to discuss the magnitude of the airflow perturbations with respect to the ideal configuration where the instrument is transparent to the wind. The generated airflow pattern is expected to induce some bias in operational measurements, especially in strong wind conditions. The proposed numerical simulation framework provides a basis to develop correction curves for the wind-induced bias of non-catching gauges, as a function of the undisturbed wind speed and direction.

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Section: Methodsmentioning

confidence: 99%

Investigation of the Wind-Induced Airflow Pattern Near the Thies LPM Precipitation Gauge

Chinchella

Cauteruccio

Stagnaro

et al. 2021

Sensors

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“…However, since fluid and solid regions have, in general, very different physical properties, appropriate time steps can be quite different for these regions. Therefore, methods such as adaptive time stepping 57 or locally varying time stepping 58 schemes can potentially improve the convergence rate and stability.…”

Section: Discussionmentioning

confidence: 99%

A unified approach for the solution of fluid‐solid interaction problems with hyperelastic deformation in internal flows

Tandis

Ashrafizadeh

2022

Numerical Methods in Fluids

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In the single domain method for solving fluid-solid interaction (FSI) problems, a unified formulation is used for the entire computational domain. In such monolithic FSI solvers, all of the governing equations are solved simultaneously. In the present study, the single domain method is further extended to an interface-tracking FSI solver which accounts for mesh movement via an Arbitrary Lagrangian-Eulerian (ALE) description of the governing equations.The focus is on internal flow problems with large deformation. Pressure and velocity are selected as the dependent variables for both solid and fluid parts of the computational domain. A distinguishing feature of the proposed method is that the governing equations at the interface are discretized in a conservative manner. Interfacial boundary conditions are enforced via a pressure-velocity splitting method to convert the kinematic and dynamic conditions at the interface into pressure-velocity relations. A PISO-like procedure is used to solve the discretized equations. In order to evaluate the proposed solver, strongly-coupled FSI benchmark test cases are employed. The performance of the proposed method and computational results are also compared with those obtained by a conventional partitioned solver. The results show that the proposed solver provides more accurate results on a coarser mesh compared to the benchmark solutions. The proposed method is also capable of solving strongly coupled problems for which the partitioned solver fails to converge.

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“…The numerical solution of the URANS equations is obtained using the OpenFOAM (Open Field Operation And Manipulation) software—an open source C++ modeling toolbox for fluid dynamics related problems (Chen et al., 2014), using the PIMPLE solver algorithm. Coupling PIMPLE with a pseudo‐transient approach based on a local time stepping numerical scheme (Jeanmasson et al., 2019) allows reducing considerably the computational burden. In this approach, the simulation is forced toward a steady state condition similarly to the Reynolds‐averaged Navier–Stokes approach, but with no need to remove the time derivative in the NS equations, therefore improving stability especially for complex geometries.…”

Section: Methodsmentioning

confidence: 99%

The Overall Collection Efficiency of Catching‐Type Precipitation Gauges in Windy Conditions

Cauteruccio,

Chinchella,

Lanza

2024

Water Resources Research

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The wind‐induced bias of catching‐type precipitation measurement instruments is quantified using Computational Fluid Dynamics with embedded liquid (raindrops) and solid (snowflakes) particle tracking. The performance of six common commercial gauges having different outer geometry is compared under a range of Precipitation Intensity (PI) and wind speed conditions by means of the numerically calculated catch ratios. Validation of the simulated aerodynamic behavior and its effect on water drop trajectories is provided by previous wind tunnel experiments. The functional dependence of the overall collection efficiency on the PI is derived as a quantitative measure of the instrument performance under a wind climatology with a uniform probability density function. Instruments with aerodynamic design produce a less pronounced diversion of hydrometeor trajectories—at any given size—than those having more traditional geometry. For liquid precipitation measurements, chimney‐shaped instruments rank low, while inverted conical and Nipher shielded instruments are quite performant solutions. The investigated quasi‐cylindrical gauges have intermediate behavior depending on their detailed aerodynamic features. For solid precipitation, all instruments rank low at light to moderate PI, except the Nipher shielded gauge. Results allow selecting the appropriate instrument for the local precipitation climatology at the measurement site and can be used to apply suitable adjustments to the measured precipitation.

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On some explicit local time stepping finite volume schemes for CFD

Cited by 10 publications

References 31 publications

Investigation of the Wind-Induced Airflow Pattern Near the Thies LPM Precipitation Gauge

Investigation of the Wind-Induced Airflow Pattern Near the Thies LPM Precipitation Gauge

A unified approach for the solution of fluid‐solid interaction problems with hyperelastic deformation in internal flows

The Overall Collection Efficiency of Catching‐Type Precipitation Gauges in Windy Conditions

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