• 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 the Korean Society for Aeronautical & Space Sciences
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• v.34 no.6
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• pp.18-28
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• 2006

Numerical analysis of high Mach number flow over a blunt-body poses many difficulties and various numerical schemes have been suggested to overcome the problems. However, the new schemes were used in the limited fields of applications because of the lack of field experience compared to more than 20 years old numerical schemes and the intricacies of modifying the existing code for the special application. In this study, some tips to overcome the numerical difficulties in solving the 3D high-Mach number flows by using Roe's scheme, the most widely used for the past 25 years and adopted in many commercial codes, were examined without a correction of the algorithm or a modification of the CFD code. The well-known carbuncle phenomena of Riemann solvers could be remedied even for an extremely high Mach number by applying the entropy fixing function and a unphysical solution could be overcome by applying a simply modified initial condition regardless of the entropy fixing and grid configuration.

• The Journal of Korean Medicine
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• v.19 no.2
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• pp.137-152
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• 1998

Acute complications of diabetes mellitus were diminished after Banting and Best discovered insulin. But chronic complications of diabetes mellitus have been increased. The main complications of diabetes mellitus are diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, diabetic foot lesion and macrovascular complication. These complications can result in renal failure, loss of sight, cerebral infarction and myocardial infarction. So it is very difficult to treat the complications of diabetes mellitus. In oriental medicine, the transformations(傳變症) of Sogal(消渴) are edema, carbuncle, loss of sight and so on. The comparative study between the trcmsformations(傳變症) of SogaI(消渴) and the complications of diabetes mellitus has come to the following conclusions. 1. In oriental medicine, diabetic retinopathy was expessed as loss of sight and the treament of diabetic retinopathy should be started at an early stage, to prevent vitreous hemorrhage and traction retinal detachment. 2. In oriental medicine. diabetic nephropathy was expressed as edema and the treatment should be started at an early stage of renal injury when the protein comes from urine.3. Symmetrical distal polyneuropathy is the main part of diabetic neuropathy and it was expressed as weakness of the lower limbs and pain of joints in the symptoms of Haso(下消). In Oriental medicine, acupuncture and herb medicine which effect is SopungHwalHyul can treat polyneuropathy. 4. Chief macrovascular complications are coronary artery disease and cerebrovascular disease, The cause of macrovascular complication is atherosclerosis. So the method of treating atherosclerosis should be studied in oriental medicine. 5. Diabetic foot were expressed as carbuncle and its main causes are decreasing perfusion of fool, diabetic neuropathy and infection. So these causes should be studied in oriental medicine. 6. The complications of diabetes mellitus afe very similar to the transfonnatiuns of Sogal(消渴).The control of blood glucose is indispensable to prevent and delay the complication of diabetes mellitus.

• Journal of computational fluids engineering
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• v.6 no.2
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• pp.32-39
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• 2001

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 chemically reacting equilibrium air was developed. The carbuncle phenomenon on detached shock in front of the payload is controlled by using pressure gradients to tune the dissipation. Chemically reacting equilibrium computations for the 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.9 no.2
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• pp.30-35
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• 2004

A numerical study of underexpanded jet and impingement on a wall mounted at various distances from the nozzle exit is presented. The 3-dimensional Wavier-Stokes equations and κ-ω turbulence equations are solved. The grids are constructed as overlapped grid systems to examine the distance effect. The DADI method is applied to obtain steady-state solutions. To avoid numerical instability such as the carbuncle phenomena that sometimes accompany approximate Riemann solver, the HLLE+ scheme is employed for the inviscid flux at the cell interfaces. A goal of this work is to apply a number of two-equation turbulence models based on the w equation to the impinging jet problem.

• Korean Journal of Pharmacognosy
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• v.14 no.3
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• pp.119-124
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• 1983

'Sochungryoung-Tang' has been known to be used in acute edema, bronchitis, pneumonia, nephrosis, and arthritis etc. in traditional chinese medicine. In this study, it was examined on the antimicrobial and anti-inflammatory activities. The following results were obtained; 1) In the antibacterial activities, the ethanol extract of 'Sochungryoung-Tang' showed to be more active than water extract aginst ten bacterials (Table I). Especially, antibacterial activities against Staphylococcus sp. showed the highest among the strains tested. But in the fungi, ethanol extract and water extract showed slightly significant effects (Table II). 2) The water extract showed significant anti-inflammatory effects against the rat hind paw edema induced by 1% carrageenin in the scab and carbuncle in the mice in fected by Staphylococcus aureus CUCC 74371.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.139-145
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• 2004

A numerical study of underexpanded jet and impingement on a wall mounted at various distances from the nozzle exit is presented. The 3-dimensional Navier-Stokes equations and $\kappa-\omega$ turbulence equations are solved. The grids are constructed as overlapped grid systems to examine the distance effect. The DADI method is applied to obtain steady-state solutions. To avoid numerical instability such as the carbuncle that sometimes accompany approximate Riemann solver, the HLLE+ scheme is employed for the inviscid flux at the cell interfaces. A goal of this work is to apply a number of two-equation turbulence models based on the $\omega$ equation to the impinging jet problem.

• Journal of computational fluids engineering
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• v.6 no.4
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• pp.43-53
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• 2001

본 논문은 충격파 불안정성이 나타나지 않는 충격파 안정적인 수치기법의 개발을 목표로 하고 있다. Roe의 수치기법은 유동의 수치계산에 있어 높은 정확도를 보장하지만 carbuncle 현상과 같은 충격파 불안정성이 나타나는 것으로 알려져 있다. Roe의 수치기법과 HLLE 수치기법의 수치점성을 비교하여 충격파 불안정성의 원인을 살펴보았으며, Roe의 수치기법에 나타나는 반감쇠항에 마하수의 함수인 조절함수 f와 g를 도입하여 충격파 안정성을 획득하였다. 본 논문에서 제안된 수치기법을 다양한 유동문제에 적용하여 수치기법의 충격파 안정성과 정확성을 검증하였다

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.99-104
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• 2001

This paper deals with the development of shock stable scheme that is free from shock instability. Roe's FDS is known to preserve good accuracy but to suffer from shock instability, i.e. the carbuncle phenomenon. As the first step toward the shock stable scheme, Roe's FDS is compared with HLLE scheme to identify the source of shock instability. Then control function f is introduced into the pressure term in Roe's FDS to cure shock instability. Various numerical tests concerned with shock instability are performed to demonstrate the shock stability of the proposed scheme.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.156-157
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• 2003

A simple method is proposed to split the flux vector of the Euler equations by introducing two artificial wave speeds. The direction of wave propagation can be adjusted by these two wave speeds. This idea greatly simplifies the upwinding, and leads to a new family of upwind schemes. Numerical flux function for multi-dimensional Euler equations is formulated for any grid system, structured or unstructured. A remarkable simplicity of the scheme is that it successfully achieves one-sided approximation for all waves without recourse to any matrix operation. Moreover, its accuracy is comparable with the exact Riemann solver. For 1-D Euler equations, the scheme actually surpasses the exact solver in avoiding expansion shocks without any additional entropy fix. The scheme can exactly resolve stationary contact discontinuities, and it is also freed of the carbuncle problem in multi­dimensional computations.