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.

Development of an Unsteady Vortex Lattice Method to Model Propellers at Incidence

Abstract: The complex aerodynamics of a propeller at incidence involve multiple asymmetric flow conditions around the disk, with each originating from different physical phenomena. These asymmetries give ris...

CFD and VLM Simulation of the Novel Twin-body Asymmetric Flying-wing Aircraft

Abstract: Twin-body aircraft has the advantages of heavy load and long voyage, which make it suitable to execute the task. However, it also has some problems such as high-strength mid-wing requirement and no usable airport in the practical application. In order to solve these problems and promote twin-body aircraft’s adaptability, this paper conducts a research of a new type of twin-body asymmetric flying-wing aircraft (TAFA). Two kinds of simulations (CFD and VLM) are conducted to prove the effectiveness of its flight performance. The results show that the flight performance of TAFA is the best among the four different kinds of plane that can perform the same tasks.

On the sensitivity and efficiency of aerodynamic shape optimisation

Abstract: Computational fluid dynamics (CFD) has become the method of choice for aerodynamic shape optimisation of complex engineering problems. To date, however, the sensitivity of the optimal solution to numerical parameters has been largely underestimated. Meanwhile, aerodynamic shape optimisation based on high-fidelity CFD remains a computationally expensive task. The thesis consists of two research streams aimed at addressing each of the challenges identified, namely revisiting the optimal solution and developing an efficient optimisation framework. This work primarily focuses on the assessment of optimal design sensitivity and computational efficiency in gradient-based optimisation of aeronautical applications. Two benchmark cases for NACA0012 and RAE2822 aerofoil optimisation are investigated using the open-source SU2 code. Hicks-Henne bump functions and free-form deformation are employed as geometry parameterisation methods. Gradients are computed by the continuous adjoint approach. The optimisation results of NACA0012 aerofoil exhibit strong dependence on virtually all numerical parameters investigated, whereas the optimal design of RAE2822 aerofoil is insensitive to those parameter settings. The degree of sensitivity reflects the difference in the design space, particularly of the local curvature on the optimised shape. The closure coefficients of Spalart-Allmaras model affect the final optimisation performance, raising the importance of quantifying uncertainty in turbulence modelling calibration. Non-unique flow solutions are found to exist for both cases, and hysteresis occurs in a narrow region near the design point. Wing twist optimisations are conducted using two aerodynamic solvers of different levels of fidelity. A multi-fidelity aerodynamic approach is proposed, which contains three components: a linear vortex lattice method solver, an infinite swept wing solver, and a coupling algorithm. For reference, three-dimensional data are obtained using SU2. Two optimisation cases are considered, featuring inviscid flow around an unswept wing and viscous flow around a swept wing. A good agreement in terms of lift distribution and aerodynamic shape between the multi-fidelity solver and high-fidelity CFD is obtained. The numerical optimisation using the multi-fidelity approach is performed at a negligible computational cost compared to the full three-dimensional CFD solver, demonstrating the potential for use in early phases of aircraft design.

A Lagrangian vortex-lattice method for arbitrary bodies interacting with a linearized semi-Lagrangian free surface

Abstract: A Lagrangian vortex-lattice approach is presented, through which bodies of arbitrary shape, wakes shedding from them, and a free surface can be modeled using sheets of concentrated vorticity. The method accounts for a full interaction of all vortex sheets in the time domain. A damping beach is used on the external boundaries of the free-surface domain. Multiple time-step computations combined with a versatile gridding approach make the current numerical implementation suitable for solving a wide variety of hydrodynamic and low-speed aerodynamic problems. Several examples and comparisons with experimental data are presented.

Aerodynamic optimizaiton for short range UAV using vortex lattice method and wind tunnel verification

Abstract: According to the aerodynamic geometry of the UAV that operates at low Reynolds number,winglet was designed to improve the efficiency of the UAV by using vortex lattice method(VLM).Optimized designs were validated by wind tunnel tests.First,several key parameters were analyzed for winglet design.Second,the optimized winglet was obtained by the VLM for UAV at cruising state.Last,a wind tunnel test for the UAV with and without winglet was carried out.Based on comparison of VLM results to full scale measured wind tunnel test data,it can be seen that they match well during linear segment.It means that the winglet was designed properly using VLM thus the lift to drag ratio of the UAV was increased by 12%,and the roll damping was increased but the yaw damping was not changed,on the other hand,these results should provide valuable guidance in designing winglet for UAV by using VLM.