Topic
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.
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01 Jan 2015
TL;DR: This work incorporates modern software development practices, such as unit level testing and version control, into the development of an unstructured panel code, CPanel, with an object-oriented approach in C++, and results are verified using the analytical solution for flow around an ellipsoid, vortex lattice method solutions for simple planforms, as well an anchored panel code.
Abstract: Development of CPanel, an Unstructured Panel Code, Using a Modified TLS Velocity Formulation Christopher R. Satterwhite The use of panel codes in the aerospace industry dates back many decades. Recent advances in computer capability have allowed them to evolve, both in speed and complexity, to provide very quick solutions to complex flow fields. By only requiring surface discretization, panel codes offer a faster alternative to volume based methods, delivering a solution in minutes, as opposed to hours or days. Despite their utility, the availability of these codes is very limited due to either cost, or rights restrictions. This work incorporates modern software development practices, such as unit level testing and version control, into the development of an unstructured panel code, CPanel, with an object-oriented approach in C++. CPanel utilizes constant source and doublet panels to define the geometry and a vortex sheet wake representation. An octree data structure is employed to enhance the speed of geometrical queries and lay a framework for the application of a fast tree method. The challenge of accurately calculating surface velocities on an unstructured discretization is addressed with a constrained Hermite Taylor least-squares velocity formulation. Future enhancement was anticipated throughout development, leaving a strong framework from which to perform research on methods to more accurately predict the physical flow field with a tool based in potential flow theory. Program results are verified using the analytical solution for flow around an ellipsoid, vortex lattice method solutions for simple planforms, as well an anchored panel code, CBAERO. CPanel solutions show strong agreement with these methods and programs. Additionally, aerodynamic coefficients calculated via surface integration are consistent with those calculated from a Trefftz plane analysis in CPanel. This consistency is not demonstrated in solutions from CBAERO, suggesting the CHTLS velocity formulation is more accurate than more commonly used vortex core methods.
6 citations
TL;DR: In this paper, the generalized vortex lattice method for oscillating lifting surfaces in subsonic flow is extended to the supersonic planar regime, where the lifting surfaces are assumed to be convex.
Abstract: The generalized vortex lattice method for oscillating lifting surfaces in subsonic flow is extended to the supersonic planar regime.
6 citations
01 Aug 2020
TL;DR: The present investigation addresses two key issues in aerodynamic performance of a propeller–wing configuration, namely linear and nonlinear predictions with low-order numerical models and produced induced drag distribution that behaves as expected.
Abstract: The present investigation addresses two key issues in aerodynamic performance of a propeller–wing configuration, namely linear and nonlinear predictions with low-order numerical models. The develop...
6 citations
TL;DR: In this paper, a modified iteration algorithm was proposed for nonlinear VLM, which has been found to be more efficient and stable than the conventional method often adopted for NLVLM.
Abstract: VORTEX lattice method (VLM) based on inviscid theory is widely used in practice as it is very effective for aerodynamic design. As conventional VLM is not suitable for aerodynamic analysis of low-aspect-ratio wings or wings at a high angle of attack, nonlinear VLM (NLVLM) was introduced in the 1970s [1–3]. Since then, NLVLMhas been adopted frequently for aerodynamic analysis of low-aspect-ratio wings, delta wings, slender bodies, etc. (as can be found in [4–12]). In NLVLM, vortex segments of a free vortex of a horseshoe vortex system are allowed to move to be aligned with local streamlines, and this inevitably requires an iterative numerical procedure. Convergence property of the iteration algorithm employed in the calculation is therefore a very practical concern [6,8,9]. In this work, we propose a modified iteration algorithm, which has been found to be more efficient and stable than the conventional method often adopted for NLVLM.
6 citations
TL;DR: In this paper, a new numerical approach based on the Vortex Lattice Method (VLM) for the solution of the hydrodynamic performances of cambered hulls in steady planing is formulated and validated.
Abstract: A new numerical approach based on the Vortex Lattice Method (VLM) for the solution of the hydrodynamic performances of cambered hulls in steady planing is formulated and validated. Due to its fully 3D formulation, the method can be applied to both cambered and un-cambered dihedral planing surfaces of any shape without any further approximation. The exact three-dimensional wetted surface of the hull is where the body boundary condition is fulfilled. The sprays region detaching both in front of the stagnation root line and from the wet portion of the chine are modeled in the numerical scheme by means of additional vortex lattice regions. The dynamic boundary condition at the stern of the hull is non-linear with respect to the perturbation potential. Results show the dynamic pressure consistently accounts for the 3D features of the flow especially in the case of cambered planing surfaces. The numerical method is verified by a systematic analysis against semi-empirical methods and it is finally validated with experimental results on prismatic as well as cambered dihedral planing surfaces. Excellent correlations are found for both types of planing surfaces that range in the same confidence interval of higher fidelity numerical models, such as RANSE solvers.
6 citations