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.

An Analytical Investigation of Wing-Jet Interaction

Abstract: The aerodynamic interaction between the wing and an inviscid jet with Mach number nonuniformity is formulated by using a two-vortex-sheet model for the jet. One of the vortex sheets accounts for the induced jet flow and the other the induced outer flow. No additional source distribution is needed for the jet at an angle of attack. The above problem is solved by satisfying the jet and wing tangency and the jet pressure-continuity conditions and using a quasi vortex lattice method for computing the induced flow field. The latter method is derived through theoretical consideration by properly accounting for singularities present in the equations and possesses the same simplicity and generality as the conventional vortex lattice method but has a better rate of numerical convergence. The resulting system of algebraic equations is solved by Purcell's vector method. The numerical formulation is first applied to the wing-slipstream interaction problem. Results for one centered-jet configuration are compared with those predicted by some existing theories.

Study of propeller-rudder interaction based on a linear method

Abstract: A linear method which calculates the steady forces of the propeller-rudder system working in a uniform flow is presented. A propeller with an infinite number of blades is used and modelled by a bound vortex sheet, a hub vortex filament and a series of free vortex sheets with an assumption that the free vortex sheets are undisturbed by the rudder. A lifting-line analysis method is incorporated to estimate the propeller performance characteristics. The rudder is represented by vortex and source/sink filaments on its mean plane. A vortex lattice method is used to estimate the rudder performance characteristics. Comparisons of the steady forces with experiments show a reasonable agreement. A rudder located in the accelerating flow just behind a propeller experiences a pressure drag. It is shown that this drag is an internal force which is counterbalanced by an increased propeller thrust. Due to the propeller induced tangential velocities in the slipstream a rudder thrust is created and the work done by the rudder thrust is a measure of the energy recovered by the rudder. The rudder in the test cases can recover up to 40% of the rotational energy and can increase the open water efficiency by up to 1.7%.

Aerodynamic canard/wing parametric analysis for general-aviation applications

Abstract: Vortex panel and vortex lattice methods have been utilized in an analytic study to determine the two- and three-dimensional aerodynamic behavior of canard and wing configurations. The purpose was to generate data useful for the design of general aviation canard aircraft. Essentially no two-dimensional coupling was encountered and the vertical distance between the lifting surfaces was found to be the main contributor to interference effects of the three-dimensional analysis. All canard configurations were less efficient than a forward wing with an aft horizontal tail, but were less sensitive to off-optimum division of total lift between the two surfaces, such that trim drag could be less for canard configurations. For designing a general aviation canard aircraft, results point toward large horizontal and vertical distance between the canard and wing, a large wing-to-canard area ratio, and with the canard at a low incidence angle relative to the wing.

Generalized vortex lattice method for oscillating lifting surfaces in subsonic flow

Abstract: A numerical method for calculating the unsteady pressure distribution on harmonically oscillating lifting surfaces in subsonic flow is presented. The Helmholtz equation for the complex velocity potential is written in integral form and solved by discrete panels superposition, which can be recognized as a generalization of the well-known vortex lattice method. Numerical calculations are carried out for a rectangular wing and are compared with well-established literature data. The influence of chordwise and spanwise discretization, as well as wake length, on the convergence rate, is also numerically studied