SPARTACUS: An open-source unified stochastic particle solver for the simulation of multiscale nonequilibrium gas flows

Feng, Kaikai; Tian, Peng; Zhang, Jun; Fei, Fei; Wen, Dongsheng

doi:10.1016/j.cpc.2022.108607

Cited by 10 publications

(5 citation statements)

References 47 publications

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“…The key point of the DSMC method is that the effects of molecular movements and collisions are assumed to be uncoupled within a computational time step t. Specifically, the simulated particles move ballistically first, then the particles within the same cell are randomly chosen as collision pairs to assign new velocities according to the phenomenological collision models (Bird 1994). DSMC can be regarded as an operator splitting scheme to solve the Boltzmann equation (Wagner 1992;Feng et al 2023)…”

Section: Simulation Methodsmentioning

confidence: 99%

“…DSMC can be regarded as an operator splitting scheme to solve the Boltzmann equation (Wagner 1992; Feng et al. 2023), i.e. …”

Section: Simulation Methodsmentioning

confidence: 99%

“…The USP simulations are performed using the open-source code SPARTACUS (Feng et al. 2023), which has been recently developed by the authors within the framework of a widely used DSMC solver SPARTA (Plimpton et al. 2019).…”

Section: Simulation Methodsmentioning

confidence: 99%

“…The performance of SPARTACUS has been evaluated over a series of test cases covering 1-D to 3-D flows with a wide range of Knudsen numbers and Mach numbers (Feng et al. 2023).…”

Section: Simulation Methodsmentioning

confidence: 99%

“…Specifically for argon gas, ω, μ ref and T ref are set to 0.81, 2.117 × 10 −5 Pa s and 273.15 K, respectively(Bird 1994). The USP simulations are performed using the open-source code SPARTACUS(Feng et al 2023), which has been recently developed by the authors within the framework of a widely used DSMC solver SPARTA(Plimpton et al 2019). The performance of SPARTACUS has been evaluated over a series of test cases covering 1-D to 3-D flows with a wide range of Knudsen numbers and Mach numbers(Feng et al 2023).…”

mentioning

confidence: 99%

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Effect of thermal fluctuations on spectra and predictability in compressible decaying isotropic turbulence

Ma,

Yang,

Chen

et al. 2024

J. Fluid Mech.

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This study investigates the impact of molecular thermal fluctuations on compressible decaying isotropic turbulence using the unified stochastic particle (USP) method, encompassing both two-dimensional (2-D) and three-dimensional (3-D) scenarios. The findings reveal that the turbulent spectra of velocity and thermodynamic variables follow the wavenumber (k) scaling law of ${k}^{(d-1)}$ for different spatial dimensions $d$ within the high wavenumber range, indicating the impact of thermal fluctuations on small-scale turbulent statistics. With the application of Helmholtz decomposition, it is found that the thermal fluctuation spectra of solenoidal and compressible velocity components ( ${\boldsymbol {u}}_{s}$ and ${\boldsymbol {u}}_{c}$ ) follow an energy ratio of 1 : 1 for 2-D cases, while the ratio changes to 2 : 1 for 3-D cases. Comparisons between 3-D turbulent spectra obtained through USP simulations and direct numerical simulations of the Navier–Stokes equations demonstrate that thermal fluctuations dominate the spectra at length scales comparable to the Kolmogorov length scale. Additionally, the effect of thermal fluctuations on the spectrum of ${\boldsymbol {u}}_{c}$ is significantly influenced by variations in the turbulent Mach number. We further study the impact of thermal fluctuations on the predictability of turbulence. With initial differences caused by thermal fluctuations, different flow realizations display significant disparities in velocity and thermodynamic fields at larger scales after a certain period of time, which can be characterized by ‘inverse error cascades’. Moreover, the results suggest a strong correlation between the predictabilities of thermodynamic fields and the predictability of ${\boldsymbol {u}}_{c}$ .

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Section: Simulation Methodsmentioning

confidence: 99%

“…DSMC can be regarded as an operator splitting scheme to solve the Boltzmann equation (Wagner 1992; Feng et al. 2023), i.e. …”

Section: Simulation Methodsmentioning

confidence: 99%

Section: Simulation Methodsmentioning

confidence: 99%

“…The performance of SPARTACUS has been evaluated over a series of test cases covering 1-D to 3-D flows with a wide range of Knudsen numbers and Mach numbers (Feng et al. 2023).…”

Section: Simulation Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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