Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Effect of Nonequilibrium Condensation on the Oscillation of the Terminating Shock in a Transonic Airfoil Flow

천음속 익형 유동에 있어서 비평형 응축이 충격파 진동에 미치는 영향

  • Received : 2011.06.30
  • Accepted : 2011.09.20
  • Published : 2012.01.01
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Abstract

In this study, to find the effect of nonequilibrium condensation on the oscillation of the terminating shock wave in transonic flows, an NACA0014 airfoil flow with nonequilibrium condensation is analyzed using the total variation diminishing (TVD) numerical scheme. Transonic free stream Mach numbers of 0.81-0.87 are tested with variations in the stagnation relative humidity. For the same free stream Mach number and attack angle of ${\alpha}=0^{\circ}$, an increase in the stagnation relative humidity attenuates the strength of the terminating shock and reduces the oscillation of the terminating shock wave. Furthermore, for the same stagnation relative humidity, the larger the free stream Mach number becomes, the shorter the period of the oscillation shock wave is. The excursion distance of the oscillation shock increases with the free stream Mach numbers for the same stagnation relative humidity. Finally, it is found that for the same shock location, the strength of the oscillating shock facing upstream is stronger than that facing downstream.

본 연구에서는 NACA0014 천음속 익형 유동에 있어서 비평형 응축이 Terminating shock 의 진동에 미치는 영향을 TVD 수치해석을 통하여 연구하였다. 주류 마하수 0.81-0.87 에 대해 정체점 상대습도가 유동 특성에 미치는 영향이 구명되었다. 받음각 ${\alpha}=0^{\circ}$ 정체점 온도(288K) 및 주류 마하수가 동일한 경우, 정체점 상대습도의 증가는 Terminating shock 의 충격파 강도를 약화시키고 충격파의 진동수도 감소시킨다. 정체점 상대습도가 동일한 경우는 주류 마하수가 클수록 충격파의 진동수는 증가한다. 정체점 상대습도가 동일한 경우, 충격파의 이동거리는 주류 마하수가 클수록 증가하는 것으로 나타났다. 특히, 충격파가 동일한 x/c 에 위치하는 경우, Terminating shock 의 충격파 강도는 충격파가 상류로 이동할 때가 하류로 이동할 때보다 강하게 된다.

Keywords

References

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