• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.39-45
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• 2000

Hypersonic analysis on the KSR-III payload configuration has been performed using an axisymmetric Navier-Stokes code. A numerical code based on the Harten and Yee's upwind TVD scheme with simplified curve fits in the equilibrium chemically reacting air was developed. The carbuncle phenomenon on detached shock in front of the payload is controlled by using pressure gradients to tune the dissipation. Equilibrium chemically reacting computations for reentry flight conditions of Mach no. 10.2, 8, 4.9 are presented and compared with the results of calorically perfect gas.

• Journal of computational fluids engineering
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• v.8 no.4
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• pp.1-5
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• 2003

A Thin-layer Wavier-Stokes equations are applied for the hypersonic flow over blunt bodies with applications to laminar as well as turbulent flows. The equations are expressed in the forms of flux-vector splitting and explicit algorithm. The upwind schemes of Steger-Warming and Van Leer are investigated to predict accurately the heating loads along the surface of the body. A mixed scheme has been presented for the differencing the convective terms and the mixed scheme is found to be less dissipative producing accurate solutions.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.643-646
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• 1994

A method of trajectory error estimation of a hypersonic vehicle, by a covariance analysis technique is presented and discussed. The method itself is a wellkown technique, however, the thema has been rarely treated. As the importance is increasing, it is explained here and some of our newly deviced techniques are also presented.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.197-201
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• 2004

A design optimization of Sphere-Cone blunt nose hypersonic flight vehicle has been studied by using upwind Navier-Stokes method and numerical optimization method. Heat transfer coefficient and drag coefficient are selected as objective function or design constraint. Control points of Bezier curve are considered as design variable.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.1-13
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• 2002

In this paper we present numerical methods fur computations of nonequilibrium hypersonic flow of air around bodies including chemical reaction effects and present numerical result of the flow over concave corners. We developed implicit finite difference method to overcome numerical difficulties with the lack of resolution behind the shock and near the body. Using our method we were able to find details of the flow properties near the shock and body and were able to continue the computation of the flow for a long distance from the corner of the body.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.23-28
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• 1999

A mutigrid convergence acceleration technique is presented for computing hypersonic inviscid and viscous flows in equilibrium state. The governing equations are solved using an explicit Runge-Kutta method. Curve fitting data in NASA Reference Publication 1181, 1260 are used to calculate equilibrium properties. In order to ensure stability, damped prolongation and modified implicit residual smoothing are proposed. Blunt body test cases are presented to demonstrate the robustness and the efficiency in performance of the proposed methods

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1031-1038
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• 2017

In order to improve the performance of the air breathing engines, it is important to maximize the total pressure recovery through air intake. In this study, we investigated whether the Oswatitsch method, which guarantees the maximum pressure recovery for supersonic intake, is effective at hypersonic speed by compressing the intake air with the same intensity at each ramp. The non-linearity of the shock wave normal Mach number at each ramp stage was analyzed by comparing the compression ramp angle and the number of ramp to the inflow Mach number in terms of compressible thermodynamics and the operation limits of the inlet. Based on this analysis, the Oswaitisch technique yields valid conditions not only in supersonic but also hypersonic flight regime.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.562-570
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• 2009

An Experimental study was conducted on the flow characteristics and interference heating caused by a two-dimensional object protruding from a flat plate using a blow-down type of hypersonic wind tunnel. Inflow condition was a free-stream Mach number of 7.0 and a unit Reynolds number of $2.0{\times}10^6/m$. Experimental conditions were varied with three heights of protuberance for two flat plate models which have different lengths. Experimental data were obtained from Schlieren visualization images and heat flux measurements. Also, this paper suggests hypersonic experimental techniques such as boundary-layer detection method in detail. A Large separation region was observed in front of the protuberance and that region was very sensitive to the height of protuberance and the length of the flat plate. For only the highest protuberance, a severe jump of heat flux was observed at the top station among the measuring points. Measured heat flux is large when the height of protuberance is large and the length of flat plate is long.

• Advances in aircraft and spacecraft science
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• v.7 no.5
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• pp.441-458
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• 2020

Rectangular-to-Ellipse Shape Transition (REST) inlets are a class of inward turning inlets designed for hypersonic flight. The aerodynamic design of REST inlets involves very complex flows and shock-wave patterns. These inlets are used in highly integrated propulsive systems. Often the design of these inlets may require many geometrical constraints at different cross-section. In present work a design approach for hypersonic inward-turning inlets, adapted for REST inlets, is coupled with a multi-objective optimization procedure. The automated procedure iterates on the parametric representation and on the numerical solution of a base flow from which the REST inlet is generated by using streamline tracing and shape transition algorithms. The typical design problem of optimizing the total pressure recovery and mass flow capture of the inlet is solved by the proposed procedure. The accuracy of the optimal solutions found is discussed and the performances of the designed REST inlets are investigated by means of fully 3-D Euler and 3-D RANS analyses.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.126-131
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• 2004

The interaction between the hypersonic free stream and the side jet flow at high altitudes is investigated by direct simulation Monte Carlo(DSMC) method. Since there is a great difference in density between the free stream and the side jet flow, the weighting factor technique which could control the number of simulation particles, is applied to calculate these two flows simultaneously. Chemical reactions are not considered in the calculation. For validation, the corner flow passing between a pair of plates that are perpendicularly attached is solved. The side jet flow is then injected into this comer flow and solution is found for the merged flow. Results are compared with the experiments. For a more realistic rocket model, the flow past a blunted cone cylinder shape is solved. The leeward or windward jet injection is merged with this flow. The effect on the rocket surface is observed at various flow angles. The lambda effect and the wake structure are found like low attitudes. High interaction between the free stream and the side jet flow is observed when the side jet is injected in the windward direction.