Numerical simulation of aircraft’s flutter is rather expensive and time-consuming. In order to save expense and calculating time, we apply first-order approximate conditions to solve the unsteady transonic Euler equations coupled with aeroelastic equations. Assuming that the airfoil is thin and undergoes small deformation, we implement wall boundary conditions on nonmoving mean wall positions. ...

In the present paper, the numerical calculation of transonic equilibria, first introduced with the FLOW code in Guazzotto et al. [Phys. Plasmas 11, 604 (2004)], is critically reviewed. In particular, the necessity and effect of imposing explicit jump conditions at the transonic discontinuity are investigated. It is found that “standard” (low-b, large aspect ratio) transonic equilibria satisfy t...

Introduction T HE propulsion system of a short takeoff and vertical landing aircraft, such as the F-35 Joint Strike Fighter, must operate over a wide range of conditions, provide good fuel efficiency at cruise, and deliver high thrust in augmented mode for transonic acceleration and supersonic operation. The propulsion system must be efficient for both high-speed flight and during hover, while ...

Critical points arising in transonic flow profiles of the steady compressible Euler equations with heat conduction are investigated. Two examples of transonic flow profiles are studied, namely, radial outflow in a gravitational field, and flow in a quasi-one-dimensional nozzle. The stationary flow equations are reformulated in terms of a dynamical system that parametrizes the flow profiles. Add...

The use of a high molecular weight test gas to increase the Reynolds number range of transonic wind tunnels is explored. Modifications to a small transonic wind tunnel are described and the real gas properties of the example heavy gas (sulfur hexafluoride) are discussed. Sulfur hexafluoride is shown to increase the test Reynolds number by a factor of more than 2 over air at the same Mach number...

Spherically symmetric transonic accretion of a fractal medium has been studied in both the stationary and the dynamic regimes. The stationary transonic solution is greatly sensitive to infinitesimal deviations in the outer boundary condition, but the flow becomes transonic and stable, when its evolution is followed through time. The evolution towards transonicity is more pronounced for a fracta...

(2006) Laser-optical investigation of stator-rotor interaction in a transonic turbine, 1 ABSTRACT This paper presents research in a highly-loaded cold-flow transonic turbine under continuous and engine like conditions. Special focus was placed on blade row interaction at app. 10600 rpm. While the first step was the investigation of a single stage machine (stator-rotor), the second step extended...

It is well-known that stationary transonic solutions of the compressible Euler equations are hard to compute using the stationary form of the equations. Therefore, time marching methods with explicit or implicit time integration are normally employed. In this paper a method is described that computes one-dimensional transonic flows directly from the stationary equations. The method is based on ...

This paper studies the liquid to vapor phase transition in a cone shaped nozzle. Using the geometric method presented in [32, 34], we further develop results on subsonic and supersonic evaporation waves in [14] to transonic waves. It is known that transonic waves do not exist if restricted solely to the slow system on the slow manifolds [14]. Thus we consider the existence of transonic waves th...

An efficient algorithm is described for calculating stationary one-dimensional transonic outflow solutions of the compressible Euler equations with gravity and heat source terms. The stationary equations are solved directly by exploiting their dynamical system form. Transonic expansions are the stable manifolds of saddle-pointtype critical points, and can be obtained efficiently and accurately ...