A. . Satyanarayana

Bio: A. . Satyanarayana is an academic researcher from Defence Research and Development Laboratory. The author has contributed to research in topics: Freestream & Pitching moment. The author has co-authored 1 publications.

Effect of Intake Geometry on Longitudinal Aerodynamics of Airbreathing Vehicles

Abstract: A wind-tunnel test program was conducted to generate a systematic aerodynamic database for airbreathing vehicles. Generic models consisting of tangent ogival nose, cylindrical body with cruciform intakes or twin intakes were tested at freestream Mach numbers ranging from 0.5 to 3.0. The length and span of intakes were varied. The intakes were two-dimensional with blocked entry. Normal force and pitching moment were nondimensionalized using planform area and distance of centroid (from nose tip) of the planform of the model rather than body cross-sectional area and body diameter, which are traditionally used. When normal-force and pitching-moment coefficients nondimensionalized this way are plotted against angle of incidence, the coefficients of different configurations coalesce for zero roll. In addition, data for different roll angles are found to coalesce when an empirical function of roll angle is introduced in the nondimensionalizing. A prediction method was developed to estimate the normal force and pitching moment of similar body-intake configurations based on this trend. Nomenclature A = cross-sectional area A B = body cross-sectional area of the configuration, = πr 2 A P = planform area of configuration APB = planform area of body API = planform area of intakes alone, A P − APB A R = reference area (equal to A P unless otherwise specified) Cdn = crossflow drag coefficient of circular cylindrical section Cm = pitching-moment coefficient about nose, M p/ qA R X CmNL = nonlinear component of pitching-moment coefficient about nose C N = normal-force coefficient, = N/ qA R C N NL = nonlinear component of normal-force coefficient cn = local normal-force coefficient per unit length d = body diameter H = height of air intake l = length of model li = length of air intake M = freestream Mach number M p = pitching moment about nose N = normal force q = freestream dynamic pressure r = body radius s = total span of body-intake configuration W = width of air intake

Mixed-Compression Supersonic Intake and Engine–Airframe Integration

Abstract: Hypersonic flight is gaining increasing attention by aerospace companies interested in designing and developing reusable aircraftlike vehicles (spaceplanes). Advanced concepts include a combination of space and aviation approaches able to fly few minutes in space for sightseeing or fast enough to enable point-to-point transportation. In this framework, a concept of hypersonic systems for space travel and high-speed transportation is presented, with a particular focus on the intake and engine–airframe configurations. The adopted intake is designed to ensure an efficient functioning, not only in nominal conditions but along the supersonic ascent trajectory thanks to a movable inner spike. A nonzero angle of attack resulted in a little degradation of the performances in terms of efficiency, spillage, and flow distortion. In the second part, the interaction between the engine and airframe is also investigated. An initial configuration, characterized by the propulsion system located on the fuselage side near the wing, is characterized by a strong interference responsible for an off-design functioning with a high percentage of air spillage. An alternative solution with engine–wing integration exhibits a completely different behavior with interference minimized, resulting in a design intake functioning without air spillage and a considerable drag reduction.