Evaluation of Viscous Flow Solvers with Adaptive Cartesian Meshes for Hypersonic Flows

Sekhar, Susheel Kumar; Zaki, Mina; Ruffin, Stephen M.; Kolobov, Vladimir; Arslanbekov, Robert

doi:10.2514/6.2011-4035

Cited by 2 publications

(1 citation statement)

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“…The developed solver is ready to be linked with finite-rate chemistry solvers using multitemperature reaction rates (for electrons, gas species, and vibrational states of molecules). The nonlinear source and loss terms for charged and neutral species can be treated using several techniques, such as a point-implicit approach [62], high-order Runge-Kutta techniques with adaptive timestepping, as well as explicit techniques. The plan is to treat the species transport and finite-rate chemistry in a fully coupled way, as commonly used in CFD for modeling combustion and flames with complex and often stiff chemistries.…”

Section: Discussionmentioning

confidence: 99%

Implicit and coupled fluid plasma solver with adaptive Cartesian mesh and its applications to non-equilibrium gas discharges

Arslanbekov

Kolobov

2021

Plasma Sources Sci. Technol.

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We present a new fluid plasma solver with adaptive Cartesian mesh (ACM) based on a full-Newton (nonlinear, implicit) scheme for non-equilibrium gas discharge plasma. The electrons and ions are described using drift–diffusion approximation coupled to Poisson equation for the electric field. The electron-energy transport equation is solved to account for electron thermal conductivity, Joule heating, and energy loss of electrons in collisions with neutral species. The rate of electron-induced ionization is a function of electron temperature and could also depend on electron density (important for plasma stratification). The ion and gas temperature are kept constant. The transport equations are discretized using a non-isothermal Scharfetter–Gummel scheme to resolve possible large temperature gradients in the sheaths. We demonstrate the new solver for simulations of direct current (DC) and radiofrequency (RF) discharges. The implicit treatment of the coupled equations allows using large time steps. The full-Newton method (FNM) enables fast nonlinear convergence at each time step, offering significantly improved simulation efficiency. We discuss the selection of time steps for solving different plasma problems. The new solver enables solving several problems we could not solve before with existing software: two- and three-dimensional structures of the entire DC discharges including cathode and anode regions, electric field reversals and double-layer formation, the normal cathode spot and an anode ring, moving striations in diffuse and constricted DC discharges, and standing striations in RF discharges. The developed FNM-ACM technique offers many benefits for tackling the disparity of gas discharge plasma systems' time scales and nonlinearity.

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Section: Discussionmentioning

confidence: 99%