Investigation on a coupled Navier–Stokes–Direct Simulation Monte Carlo method for the simulation of plume flowfield of a conical nozzle

Tang, Zhenyu; He, Bijiao; Cai, Guobiao

doi:10.1002/fld.3924

Cited by 20 publications

(10 citation statements)

References 30 publications

(69 reference statements)

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“…To form the N-S/DSMC-coupled solver, several techniques have been investigated, including the mixing of statebased and flux-based coupling schemes, Cartesian grids and quadrilateral structured grids interpolation method, which are described in Ref. [11]. The Kn GL is used as the continuum breakdown parameter in the current study, which is defined as:…”

Section: Coupled N-s/dsmc Methodsmentioning

confidence: 99%

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Investigation on the Interface Smoothing of Coupled N–S/DSMC Method Using Image Processing Filters

Cai

Tang

Wei

2018

Adv. Astronaut. Sci. Technol.

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Gas flow problems involving both continuum and rarefied regimes are common in many scientific and engineering applications. Coupled N-S/DSMC method is a major solution to simulate the continuum-rarefied transitional flow. Interface determination is one of the key aspects in developing coupled N-S/DSMC solver, which is often implemented using continuum breakdown parameters to indicate the rarefication level. Due to the statistics characteristic of DSMC method, distribution of the continuum breakdown parameters usually fluctuates, resulting in difficulty in locating the interface. Considering the similarity between continuum breakdown parameter smoothing and noise reduction in image processing, a general smoothing method is proposed in this paper, which employs the image filters to smoothen the distribution of continuum breakdown parameters. Two commonly used image filters, the mean filter and the median filter, are investigated. Several comparison studies are implemented by simulating a typical vacuum plume impingement flow problem. The median filter with 5 × 5 mask provides the best performance. The flow problem of flow over a 2D cylinder is used to validate the coupled N-S/DSMC solver using median filter to smoothen continuum breakdown parameter, which proves the accuracy of the coupled solver and validity of the smoothing method.

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Section: Coupled N-s/dsmc Methodsmentioning

confidence: 99%

“…Former coupled N-S/DSMC solvers [9][10][11] must have had considered this problem in some manner, but no special research has focused on it. In the present paper, investigations are performed on this subject, aiming to find a general solution for coupled N-S/DSMC method to locate the interface more reliably and flexibly.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Interface Smoothing of Coupled N–S/DSMC Method Using Image Processing Filters

Cai

Tang

Wei

2018

Adv. Astronaut. Sci. Technol.

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“…(38) with N s = 100. The kinetic equation (22) is solved by the second-order upwind scheme, while the derivative in Eq. (53) is approximated by the central finite difference scheme with 5 stencils, and the resulting linear algebraic system for U 1 is solved exactly in the bulk region (i.e.…”

Section: Oscillatory Couette Flow Between Two Parallel Platesmentioning

confidence: 99%

“…There has been a tremendous growth of researches on multiscale hybrid numerical methods that combine multiple models defined at fundamentally different length and time scales within the same overall spatial and temporal domain. Specifically for the flow of interest, the continuum CFD methods are used in regions where the Navier-Stokes equations are valid, while methods based on gas kinetic theory are applied in regions where the continuum equations fail [16,17,18,19,20,21,22]. However, intrinsic difficulties arises when coupling the two different models.…”

Section: Introductionmentioning

confidence: 99%

Can we find steady-state solutions to multiscale rarefied gas flows within dozens of iterations?

Zhu

Wang

et al. 2020

Journal of Computational Physics

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One of the central problems in the study of rarefied gas dynamics is to find the steady-state solution of the Boltzmann equation quickly. When the Knudsen number is large, i.e. the system is highly rarefied, the conventional iteration scheme can lead to convergence within a few iterations. However, when the Knudsen number is small, i.e. the flow falls in the nearcontinuum regime, hundreds of thousands iterations are needed, and yet the "converged" solutions are prone to be contaminated by accumulated error and large numerical dissipation. Recently, based on the gas kinetic models, the implicit unified gas kinetic scheme (UGKS) and its variants have significantly reduced the iterations in the near-continuum flow regime, but still much higher than that of the highly rarefied gas flows. In this paper, we put forward a general synthetic iteration scheme (GSIS) to find the steady-state solutions of general rarefied gas flows within dozens of iterations at any Knudsen number. The key ingredient of our scheme is that the macroscopic equations, which are solved together with the Boltzmann equation and help to adjust the velocity distribution function, not only asymptotically preserves the Navier-Stokes limit in the framework of Chapman-Enskog expansion, but also contain Newton's law for stress and Fourier's law for heat conduction explicitly. For this reason, like implicit UGKS, the constraint that the numerical cell size should be smaller than the mean free path of gas molecules is removed, but we do not need the complex evaluation of numerical flux at the cell interface. What's more, as the GSIS does not rely on the specific kinetic model/collision operator, it can be naturally extended to quickly find converged solutions for mixture flows and even flows involving chemical reactions. These two superior advantages are also expected to accelerate the slow convergence in simulation of near-continuum flows via the direct simulation Monte Carlo method and its low-variance version. * Wei Su and Lianhua Zhu contribute equally.

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“…From 1990’s, the continuum method and the DSMC method have been combined to simulate a continuum-rarefied flow together by several researchers [ 9 – 11 ]. In recent, Tang et al introduced a possessing adaptive-interface and two-way coupling features for the DSMC solver for the simulation of the nozzle and plume flows of a heated nitrogen thruster [ 12 ]. Also, Grabe et al [ 13 ] focused on the means to compare the computed flow field data to experimental results using nitrogen flow emanating from a conical nozzle.…”

Section: Introductionmentioning

confidence: 99%

Numerical comparison of exhaust plume flow behaviors of small monopropellant and bipropellant thrusters

Lee

2017

PLoS ONE

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In general, a space propulsion system has a crucial role in the normal mission operations of a spacecraft. Depending on the types and number of propellants, a monopropellant and a bipropellant thrusters are mostly utilized for low thrust liquid rocket engines. As the plume gas flow exhausted from these small thrusters expands freely in a vacuum space environment along all directions, adverse effects of the plume impingement onto the spacecraft surfaces can dramatically reduce the function and performance of a spacecraft. Thus, the purpose of the present study is to investigate and compare the major differences of the plume gas flow behaviors numerically between the small monopropellant and bipropellant thrusters. To ensure efficient numerical calculations, the whole physical domain was divided into three different subdomains depending on the flow conditions, and then the appropriate numerical methods were combined and applied for each subdomain sequentially. With the present analysis results, the plume gas behaviors including the density, the overall temperature and the separation of the chemical species are compared and discussed between the monopropellant and the bipropellant thrusters. Consequently, the present results are expected to provide useful information on selecting the appropriate propulsion system, which can be very helpful for actual engineers practically during the design process.

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Investigation on a coupled Navier–Stokes–Direct Simulation Monte Carlo method for the simulation of plume flowfield of a conical nozzle

Cited by 20 publications

References 30 publications

Investigation on the Interface Smoothing of Coupled N–S/DSMC Method Using Image Processing Filters

Investigation on the Interface Smoothing of Coupled N–S/DSMC Method Using Image Processing Filters

Can we find steady-state solutions to multiscale rarefied gas flows within dozens of iterations?

Numerical comparison of exhaust plume flow behaviors of small monopropellant and bipropellant thrusters

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