Time accurate numerical simulations are performed for the flow field around a vonKárman ogive with fineness ratio of 3.5 under the plasma actuation near the nose tip in a freestream of M=0.1 and Re D =220,000 to evaluate the effects of the actuation. The moving wall boundary condition is employed to model the plasma actuation. The velocity of the moving wall is correlated by the momentum produced by the plasma actuator on a flat plate using PIV measurements. The flow separation is promoted so that the pressure increases and the vortex is lifted up on the actuation side. Steady side forces with increasing magnitude are observed with increasing moving wall velocity. Increasing the moving wall velocity increases the rate of spatial evolution of the vortex asymmetry in the axial direction. The behavior of the side force observed in the simulation in terms of direction and magnitude in response to the actuation agrees with the observations in the wind tunnel test conducted by the authors under the same model geometry and freestream condition. NomenclatureC p = pressure coefficient Cz = force coefficient in the yaw direction (positive toward the port from the starboard) D = Base diameter of the ogive model M = Mach number Re D = Reynold's number based on D U ∞ = Magnitude of the freestream velocity U w = Magnitude of the moving wall velocity u = Velocity component in the horizontal direction v = Velocity component in the vertical direction x = Longitudinal axis of the ogive model (positive toward the base from the nose)  = Angle of attack

The jet impinging flow stl"Ucture exhibits such complex natures as shock shell, plate shock, and Mach disk, depending on the flow parameters. The main pammeters are the ratio of the jet pressUl'e to the ambient preSSUl'e and the distance between the nozzle and the wall. Complexity and unsteadiness of this flow pose quite a numerical challenge for the flux-difference line of schemes, defying easy capture of the plate shock and l'ecirculation zone at the jet center. Such difficulties are overcome and stable solutions are obtained first fOl' jet impingement on a flat plate and then within a vertical launching system, yielding locations, as well as magnitudes of maximum pressUl'e and heat flux for hardw3l'e designers. The plate shock and wall pressure beneath are found to oscillate with a frequency between 1 and 10 kHz, depending on the flow condition.

The side jet effects between jet flow and free-stream on a missile body were investigated by experimentally and numerically for modeling aerodynamic coefficients in pitch plane. K-factors for normal force and pitching moment were introduced to estimate the side jet effects. The main parameters of the jet interaction phenomena were angle of attack, jet pressure ratio, Mach number and jet bank angle. The K-factors for normal force coefficient and pitching moment coefficients in pitch plane were analysed.

This study analyzed passenger access and egress travel patterns related to a Korean regional railway station (Seoul station), then developed a binomial logit model. This model referred to bus and metro mode of access and egress during a national holiday (Chuseok 2009); obtained from transit smart card data. The results showed that 99% of passengers getting access to, or egress from, the regional railway station did so using less than two transfers, and that most passengers were more likely to choose a metro. However, the passengers that made access or egress trips near Seoul Station were more likely to take a bus. From the results of the mode choice model, it was found that the impact of travel time was greater than that of travel cost, in the choices made for both access and egress. Interestingly, the impact of travel time is much greater in choosing the mode of egress.

No abstract