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 2011
TL;DR: In this article, an integral simulation model for flexible aircraft and its application to the flight loads analysis of wake vortex encounters of a large transport aircraft is described. But the model is not suitable for the simulation of large aircraft.
Abstract: This report describes the development of an integral simulation model for flexible aircraft and its application to the flight loads analysis of wake vortex encounters of a large transport aircraft. The aerodynamic model consists of a databank containing the steady aerodynamic loading oft the quasi-flexible aircraft combined with an unsteady vortex lattice method for lifting surfaces and bodies. To improve accuracy and computational performance, a correction method based on steady reference data and an order reduction method are introduced. Aeroelastic coupling of the aeroelastic model to the structural model is achieved by a method based on finite interpolation beam elements. A parameterized wake vortex encounter is used to determine the loads-critical encounter type and to illustrate the impact of aircraft modeling on the obtained loads.
7 citations
01 Dec 2006
TL;DR: In this article, a single propeller hull diffraction method was combined with a Vortex Lattice Method (MPUF3A) to solve for the unsteady sheet cavitation on the propeller blades.
Abstract: A previously developed method which solves for the diffraction potential on the hull subject to the presence of a single propeller (HULLFPP) is coupled with a Vortex Lattice Method (MPUF3A) which solves for the unsteady sheet cavitation on the propeller blades. Systematic studies on grid dependence of cavity solution, propeller forces and hull pressure fluctuations are performed in the case of single propellers. The effects of the presence of tunnel wall or free surface on the predicted pressure fluctuations on the hull are also investigated. The method is then extended to the case of twin propellers. Comparisons between the numerical results and those measured in existing experiments are presented.
7 citations
01 Jan 1976
TL;DR: A review of the beginning and some orientation of the vortex-lattice method were given in this paper, followed by its field of computational fluid dynamics, spanning the period from L.F. Richardson's paper in 1910 to 1975, including numerical analysis of partial differential equations, lifting-line theory, finite difference method, 1/4-3/4 rule, block relaxation technique, application of electronic computers, and advanced panel methods.
Abstract: A review of the beginning and some orientation of the vortex-lattice method were given. The historical course of this method was followed in conjunction with its field of computational fluid dynamics, spanning the period from L.F. Richardson's paper in 1910 to 1975. The following landmarks were pointed out: numerical analysis of partial differential equations, lifting-line theory, finite-difference method, 1/4-3/4 rule, block relaxation technique, application of electronic computers, and advanced panel methods.
7 citations
TL;DR: The meaning of low-order and highorder methods from the steady aerodynamic sense is clarified and it is demonstrated that ZONA6 requires fewer aerodynamic boxes than the DLM for a converged unsteady aerodynamic solution.
Abstract: T HE purpose of this Note is to clarify the frequency-dependence issue of ZONA6 and the doublet-lattice method (DLM) commented on by Rodden [1]. The DLM [2] is an unsteady flow extension of the vortex-lattice method (VLM) that was proposed by Hedman [3] and Belotserkovskii [4] during the mid-1960s to compute the steady aerodynamics on lifting surfaces. The VLM is a low-order steady aerodynamic panel method, because the vortex singularity is concentrated along the quarter-chord line on each aerodynamic box. By the mid-1970s, Woodward’s method [5] further advanced the steady panel methods with a distributed singularity over the complete aerodynamic box, and they are therefore higher-order methods than VLM. ZONA6 [6] is an unsteady flow extension of Woodward’s method and is therefore a higher-order method than the DLM. In this Note, we first clarify the meaning of low-order and highorder methods from the steady aerodynamic sense. Then the comparison between the ZONA6 and DLM solutions on the BAH wing [7] is presented to demonstrate that ZONA6 requires fewer aerodynamic boxes than the DLM for a converged unsteady aerodynamic solution.
7 citations
TL;DR: In this article, an augmented system is constructed from Marcov parameters which are derived from an appropriate numerical computation of un-steady aerodynamics, which is expressed by using augmented system which is strictly proper and of finite dimension.
Abstract: expressed by using augmented system which is strictly proper and of finite dimension The augmented system is constructed from Marcov parameters which are derived from an appropriate numerical computation of un- steady aerodynamics A simple example is given to illustrate the approximation properties of the model The characteristics of the model are: 1) no complex parameters are necessary to determine the model, 2) system stability of the model is easily guaranteed, and 3) accuracy of the model is good in both the high- and low- frequency regions Nomenclature = coefficient matrices of the nonmemory component in unsteady aerodynamics = aerodynamic matrix in the frequency domain = reference semichord (length) = pressure difference between upper and lower surfaces of the wing, dimensionless with respect to YipV2 -- impulse response of nondimensiona l pressure difference produced by the third- order derivative of they'th mode input = generalized force, dimensionless with respect
7 citations