• Title/Summary/Keyword: 항력 발산 마하수

Search Result 3, Processing Time 0.023 seconds

Aerodynamic performance of Modified Sonic Arc Airfoil (수정 Sonic Arc 익형의 공력성능)

  • Lee, Jang-Chang
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.35 no.7
    • /
    • pp.581-585
    • /
    • 2007
  • Sonic arc airfoil derived from the TSD theory is modified to new airfoil shape and its aerodynamic performance in transonic flow is investigated. The numerical simulation using Euler equations for the modified sonic arc airfoil is performed. The numerical results are compared with the aerodynamic performance of NACA0012 airfoil, of supercritical airfoil, and of NACA64A210 airfoil. In the same free stream Mach number of transonic flow, the pressure drag of the modified sonic arc airfoil is smaller than that of NACA0012 airfoil and the lift-drag ratio of the modified sonic arc airfoil is much larger than that of NACA0012 airfoil. In the comparison of the drag-divergence Mach number of transonic flow, the drag-divergence Mach number of the modified sonic arc airfoil is larger than that of NACA64A210 airfoil but is smaller than that of supercritical airfoil.

Numerical Study on the Effect of Non-Equilibrium Condensation on Drag Divergence Mach Number in a Transonic Moist Air Flow (천음속 익형 유동에서 비평형 응축이 Drag Divergence Mach Number에 미치는 영향에 관한 수치 해석적 연구)

  • Choi, Seung Min;Kang, Hui Bo;Kwon, Young Doo;Kwon, Soon Bum
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.40 no.12
    • /
    • pp.785-792
    • /
    • 2016
  • In the present study, the effects of non-equilibrium condensation on the drag divergence Mach number with the angle of attack in a transonic 2D moist air flow of NACA0012 are investigated using the TVD finite difference scheme. For the same ${\alpha}$, the maximum upstream Mach number of the shock wave, Mmax, and the size of supersonic bubble decrease with the increase in ${\Phi}_0$. For the same $M_{\infty}$, ${\Phi}_0$, and $T_0$, the length of the non-equilibrium condensation zone ${\Delta}_z$ decreases with increasing ${\Phi}_0$. On the other hand, because of the attenuating effect of non-equilibrium condensation on wave drag, which is related to the interaction between the shock wave and the boundary layer, the drag coefficient $C_D$ decreases with an increase in ${\Phi}_0$ for the same $M_{\infty}$ and ${\alpha}$. For the same ${\alpha}$, $M_D$ increases with increasing ${\Phi}_0$, while $M_D$ decreases with an increase in ${\alpha}$.

AERODYNAMIC ANALYSIS ON LEADING-EDGE SWEEPBACK ANGLES OF FLYING-WING CONFIGURATIONS (전익기 형상의 앞전후퇴각 변화에 따른 공력해석)

  • Lee, J.M.;Chang, J.W.
    • Journal of computational fluids engineering
    • /
    • v.11 no.4 s.35
    • /
    • pp.48-55
    • /
    • 2006
  • A computational study was carried out in order to investigate aerodynamic characteristics on leading edge sweepback angles of Flying-Wing configurations. The viscous-compressible Navire-Stokes equation and Spalart-Allmaras turbulence model of the commercial CFD code were adopted for this computation analysis. This investigation examined aerodynamic characteristics of three different types of leading edge sweepback angles: $30^{\circ}C,\;35^{\circ}C\;and\;40^{\circ}C$. The freestream Mach number was M=0.80 and the angle of attack ranged from ${\alpha}=0^{\circ}C\;to\;{\alpha}=20^{\circ}C$. The results show that the increases in sweepback angle of the Flying-Wing configuration creates more efficient aerodynamic performance.