Improved parallelized hybrid DSMC–NS method

Lian, Y. Y.; Chen, Yen-Sen; Tseng, Kuo-Hung; Wu, Jong-Shinn; Wu, B. H.; Yang, Lijun

doi:10.1016/j.compfluid.2010.12.015

Cited by 15 publications

(9 citation statements)

References 14 publications

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“…Figure a gives four photographs that show the interfaces. According to Lian et al (), Thiruvenkadam (), and Figure a, the possible interfaces are shown in Figure b. Therefore, the radio link between the antenna equipped on an aircraft and the antenna carried on a satellite or placed at an Earth station may cross one interface or some interfaces.…”

Section: The Fresnel Reflection Of An Electromagnetic Wave At the Intmentioning

confidence: 99%

“…According to Fox et al (), the ideal thickness of a shock wave interface is about 10 −4 mm, which means that a shock wave interface can be regarded as a geometrical surface with good approximation. In practical, the thickness of the shock wave interface and the inner interfaces are closely related to the parameters of free flow, such as temperature T ∞ , pressure P ∞ , density ρ ∞ , the relative velocity Ma ∞ , and the shape and the flight attitude of aircraft (Lian et al, ). The Hybrid Direct Simulation Monte Carlo‐Navier Stokes method given by Lian et al () can simulate the thickness of the interfaces.…”

Section: The Fresnel Reflection Of An Electromagnetic Wave At the Intmentioning

confidence: 99%

“…In practical, the thickness of the shock wave interface and the inner interfaces are closely related to the parameters of free flow, such as temperature T ∞ , pressure P ∞ , density ρ ∞ , the relative velocity Ma ∞ , and the shape and the flight attitude of aircraft (Lian et al, ). The Hybrid Direct Simulation Monte Carlo‐Navier Stokes method given by Lian et al () can simulate the thickness of the interfaces. It is shown that the thickness of the interfaces in the supersonic boundary layer airflow under the simulating conditions in Lian et al () is about 2 mm.…”

Section: The Fresnel Reflection Of An Electromagnetic Wave At the Intmentioning

confidence: 99%

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Neglected Radio Blackout Induced by the Nonionized Airflow Sheath Around a Supersonic Aircraft

et al. 2018

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The characteristics of the flow field around a supersonic aircraft are discussed. It is analyzed that there are interfaces between two adjacent regions with jump change of refractive index in the supersonic flow. The physical mechanism of the Fresnel reflection of an electromagnetic wave at the interfaces mentioned above is analyzed according to the Fresnel reflection phenomenon in the Earth atmosphere. The conditions for the Fresnel reflection in the supersonic flow field are discussed, and the formulae for calculating the Fresnel reflection coefficient are given. According to the process of a radio wave propagating across the interfaces in the supersonic flow field, the other radio blackout phenomenon is proposed for the first time, which is induced by the nonionized atmospheric sheath around a supersonic aircraft, and may be well neglected or mistaken for the plasma‐sheath‐caused radio blackout. The conditions of the nonionized‐atmospheric‐sheath‐induced radio blackout are investigated. The calculation results show that the neglected radio blackout is confined to a rather specific case, a very small range of grazing angles. However, it is significant for identifying the mechanism of radio blackout.

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Section: The Fresnel Reflection Of An Electromagnetic Wave At the Intmentioning

confidence: 99%

Section: The Fresnel Reflection Of An Electromagnetic Wave At the Intmentioning

confidence: 99%

Section: The Fresnel Reflection Of An Electromagnetic Wave At the Intmentioning

confidence: 99%

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Neglected Radio Blackout Induced by the Nonionized Airflow Sheath Around a Supersonic Aircraft

et al. 2018

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“…The adaptive-interface two-way coupling method has been used for many flow problems such as normal shock wave [7], flow over cylinder surface [14], and supersonic flow past a wedge [15], but to our knowledge regarding the problem of plume flowfield of thrusters, only the decoupled NS-DSMC method has been used in former studies. Boyd studied the nozzle and plume flows with NS and DSMC methods.…”

Section: Introductionmentioning

confidence: 99%

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

Tang

Cai

2014

Numerical Methods in Fluids

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SUMMARY To assess the plume effects of space thrusters, the accurate plume flowfield is indispensable. The plume flow of thrusters involves both continuum and rarefied flow regimes. Coupled Navier–Stokes–Direct Simulation Monte Carlo (NS–DSMC) method is a major approach to the simulation of continuum‐rarefied flows. An axisymmetric coupled NS–DSMC solver, possessing adaptive‐interface and two‐way coupling features, is investigated in this paper for the simulation of the nozzle and plume flows of thrusters. The state‐based coupling scheme is adopted, and the gradient local Knudsen number is used to indicate the breakdown of continuum solver. The nitrogen flows in a conical nozzle and its plume are chosen as the reference case to test the coupled solver. The threshold value of the continuum breakdown parameter is studied based on both theoretical kinetic velocity sampling and coupled numerical tests. Succeeding comparisons between coupled and full DSMC results demonstrate their conformities, meanwhile, the former saves 58.8% computational time. The pitot pressure evaluated from the coupled simulation result is compared with the experimental data proposed in literatures, revealing that the coupled method makes precise predictions on the experimental pitot pressure. Copyright © 2014 John Wiley & Sons, Ltd.

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“…These hybrid schemes gain the accuracy of a DSMC simulation in the rarefied regions of the flowfield while keeping the lower computational expense of a continuum algorithm. Similarly to the research that has been done in each flow regime (continuum and rarefied), parallelization is a growing area of research for these hybrid solvers [81].…”

Section: Coupling Dsmc and Navier-stokesmentioning

confidence: 99%

Open Source Toolkit for Reentry Object Modeling

Ostrom

Lloyd

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Open Source Toolkit for Reentry Object ModelingChristopher L. Ostrom II Predicting the mass, position, and velocity of an object during its reentry are critical to satisfy NASA and ESA requirements. This thesis outlines a 3-D orbit and mass determination system for use on low earth orbit as applicable to general objects, of various material and size. The solution uses analytical models to calculate heat flux and aerodynamic drag, with some basic numerical models for simple orbit propagation and mass flow rate due to ablation. The system outlined in this thesis currently provides a framework for rough estimates of demise altitude and final mass, but also allows for many potential accuracy and speed improvements. 77 aerospace materials were tested, in solid spheres, cubes, and cylinders; it was found that materials with low latent heat of fusion (less than 10

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Improved parallelized hybrid DSMC–NS method

Cited by 15 publications

References 14 publications

Neglected Radio Blackout Induced by the Nonionized Airflow Sheath Around a Supersonic Aircraft

Neglected Radio Blackout Induced by the Nonionized Airflow Sheath Around a Supersonic Aircraft

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

Open Source Toolkit for Reentry Object Modeling

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