Vortex lattice method

About: Vortex lattice method is a research topic. Over the lifetime, 779 publications have been published within this topic receiving 9242 citations.

Aeroelastic Analysis of a Turbine Cascade with Various Inter-Blade Phase Angles

Abstract: The aeroelastic analysis of the turbine cascade is generally solved in frequency domain because of the computational efficiency. Nevertheless, time domain cascade analysis is also required that the transient response analysis of the cascade is important. Model order reduction in the aeroelastic analysis is one of the techniques to overcome the excessive computational load in time domain cascade analysis. In this paper, both time and frequency domain analysis are conducted since results in both domains are important. For a cascade aerodynamic analysis, a kernel function corresponding to the vortex lattice method is used in discrete time domain. The results in mixed time and frequency domain are transferred to frequency domain by using the z transform. The results obtained by applying the z transform are used to analyze the flutter boundary of the cascade. The p transform is also used to obtain the results in time domain from the results acquired in frequency domain. This transformation can provide advantages in terms of model order reduction without additional aerodynamic states and improvement in computational efficiency. Both frequency and time domain analyses can be conducted at a time by using the present analysis for the turbine cascade.

Vortical Wakes Over a Prolate Spheroid

Abstract: The vortex-lattice method is employed to calculate the inviscid flow and the development of separated vortex sheets over a prolate spheroid. An approximate boundary-layer method based on the assumption of local similarity is used to calculate the line of open separation. A condition of vortex shedding along the separation line is proposed. The two methods of calculation, viscous and inviscid, interact through the line of separation that is allowed to displace as the wake grows. Results are compared with flow visualization data for laminar separation and pressure data for turbulent separation.

Aerodynamic Simulation of Wake Encounter for Aircraft Close Formation Operations (Invited)

Abstract: In this study, the rolling moment coefficient of a following unmanned aerial vehicle (UAV) induced by wake vortices from a leading UAV is analyzed and studied. Numerical simulation results are compared to the results from an analytical vortex lattice method. Then a complete UAV mesh is built and used to calculate the influence by a pair of wake vortices created by the leading UAV in real flight scenario. The paper provides an estimate of the vortex roll hazard assessment for the following UAV in close formation operations.

An analytical design procedure for the determination of effective leading edge extensions on thick delta wings

Abstract: An analytical design procedure for leading edge extensions (LEE) was developed for thick delta wings. This LEE device is designed to be mounted to a wing along the pseudo-stagnation stream surface associated with the attached flow design lift coefficient of greater than zero. The intended purpose of this device is to improve the aerodynamic performance of high subsonic and low supersonic aircraft at incidences above that of attached flow design lift coefficient, by using a vortex system emanating along the leading edges of the device. The low pressure associated with these vortices would act on the LEE upper surface and the forward facing area at the wing leading edges, providing an additional lift and effective leading edge thrust recovery. The first application of this technique was to a thick, round edged, twisted and cambered wing of approximately triangular planform having a sweep of 58 deg and aspect ratio of 2.30. The panel aerodynamics and vortex lattice method with suction analogy computer codes were employed to determine the pseudo-stagnation stream surface and an optimized LEE planform shape.