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.

Investigation into hub effect of marine propeller by surface vortex lattice method

Abstract: In this paper the hub effects of some model propellers are investigated by the surface vortex lattice method for the hub and by the ordinary vortex lattice method on the lifting surface for the blade. The surface, where the surface vortex lattices are distributed, is taken inside of the real surface of the hub in order to avoid the strong interference effect between the root vortex lattices of the blade and the surface vortex lattices of the hub. It is found that the hub effect is noticeable on the pressure distribution on the blade surface near the root but smaller on the outer blade surface toward the tip, but that the hydrodynamic forces of the propeller such as thrust and torque are scarcely affected by the existence of the hub of the normal size. The calculated pressure distributions on the blade including the hub effect show good or poor agreement with the measured results. The pressure distribution on the hub surface is calculated and assessed. Calculations also show that the hub effect is more significant for the larger hub diameter such as controllable pitch propellers, as expected,

Quasi-Steady Aerodynamic Analysis of Propeller-wing Interaction

Abstract: The Quasi-steady aerodynamic coupling between a propeller and a wing is analyzed using the 3-D vortex lattice method based on the unsteady lifting line theory for the propeller and the 3-D panel method based on the unsteady lifting surface theory for the wing. The periodic loads are decomposed into harmonics and the harmonic amplitudes are found iteratively. Each stage of the iteration involves the solution of an isolated propeller or wing problem, the interaction being done through the Fourier Transform of the induced velocity field. This method was validated by comparing the predicted velocity field about an isolated propeller with detailed laser doppler velocimeter measurements and by comparison with mean loads measured in a wing-propeller experiments. Comparisons have also been made among the fluctuating loads predicted by the present method an unsteady panel scheme and a quasi-steady vortex lattice scheme.

On propulsive performance of propeller and rudder system

Abstract: In this paper a numerical lifting surface method, ie, the vortex lattice method is applied for predicting the characteristics of the propeller. The propulsive performance of the propeller-rudder system is studied and a panel method is employed to describe the performance of the rudder behind the propeller. The drag of the rudder is calculated by boundary layer theory to enhance the accuracy of the prediction. Several examples are given and the calculated results and experimental data show good agreement.

Improved Uvlm for Flapping-Wing Aerodynamics Computation

Abstract: To calculate the aerodynamics of flapping-wing micro air vehicle (MAV) with the high efficiency and the engineering-oriented accuracy, an improved unsteady vortex lattice method (UVLM) for MAV is proposed. The method considers the influence of instantaneous wing deforming in flapping, as well as the induced drag, additionally models the stretching and the dissipation of vortex rings, and can present the aerodynamics status on the wing surface. An implementation of the method is developed. Moreover, the results and the efficiency of the proposed method are verified by CFD methods. Considering the less time cost of UVLM, for application of UVLM in the MAV optimization, the influence of wake vortex ignoring time saving and precision is studied. Results show that saving in CPU time with wake vortex ignoring the appropriate distance is considerable while the precision is not significantly reduced. It indicates the potential value of UVLM in the optimization of MAV design.

Analysis of wings with multi-segmented flaps using a non-planar vortex lattice method

Abstract: An important problem of analysis of complex wing planforms with multisegmented is addressed. Nonplanar vortices are used to simulate the wing incidence and camber effects, whereas thickness effects are incorporated using constant source flat panels.Important aspects of the current work are modeling of flow near wing-flap junctures,use of symmetrical singularity for calculating the strengths of the thickness sources,and efficient programming,which is a prerequisite while using nonplanar vortices and a versatile geometric package which generates automatically optimum lattice layout for rapid numerical convergence. The method was validated against a number of test cases for which results are available from experiments and other theories.