Numerical Approach to Aeroelastic Responses of Three-Dimensional Flexible Sails

1993 ◽  
Author(s):  
Toichi Fukasawa ◽  
Masanobu Katori
Keyword(s):  
Numerical Simulations ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Lattice Method ◽  
3 Dimensional ◽  
Vortex Lattice Method ◽  
Induced Drag ◽  
Displacement Theory

Aeroelastic responses of 3-dimensional flexible sails are investigated by means of numerical simulations. An incremental finite displacement theory using the Finite Element Method is adopted to describe the structural behavior of the sail. A modified Vortex Lattice Method is used to calculate the aerodynamic pressures on the sail. Combining these two methods, the structural and aerodynamic responses of the sail are solved simultaneously. Numerical simulations are performed for actual 3- dimensional sails. Deformations and stresses of the sail in steady flow are calculated. Unsteady sail dynamics are also investigated in the case where the sailing vessel is pitching and rolling in a seaway. The effects of the flexibility of the sail upon the lift, induced drag and the center of effort are clarified.

scholarly journals Induced Drag Calculations with the Unsteady Vortex Lattice Method for Cambered Wings

AIAA Journal ◽  
2017 ◽  
Vol 55 (2) ◽  
pp. 668-672 ◽  
Author(s):  
Thomas Lambert ◽  
Grigorios Dimitriadis
Keyword(s):  
Vortex Lattice ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Induced Drag

Prediction of Unsteady Effective Wake by a Euler Solver/Vortex-Lattice Coupled Method

2003 ◽  
Vol 47 (02) ◽  
pp. 131-144
Author(s):  
Jin-Keun Choi ◽  
Spyros A. Kinnas
Keyword(s):  
Vortex Lattice ◽  
Three Dimensional ◽  
Lattice Method ◽  
Coupled Method ◽  
Vortex Lattice Method ◽  
Finite Volume Approach ◽  
Euler Solver ◽  
Effective Wake ◽  
Total Velocity ◽  
Surface Vortex

A fully three-dimensional Euler solver, based on a finite volume approach, is developed and applied to the prediction of the unsteady effective wake for propellers subject to non-axisymmetric inflows. The Euler solver is coupled with an existing lifting-surface vortex-lattice method for the computation of unsteady propeller flows. The coupled method is validated against the uniform inflow case, in which ideally the uniform flow should be recovered as the effective wake. The predicted total velocity field correlates very well with that measured in the water tunnel experiment. Lastly, the unsteady effective wake predicted by the present method is compared with the steady effective wake predicted by the authors' previous steady method.

3D Simulation of a Convergent-Divergent Aero Engine Intake, Using Two Different CFD Methods

2005 ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Geoffrey Guindeuil ◽  
Theodoros Lekas ◽  
Vassilios Pachidis
Keyword(s):  
Vortex Lattice ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Internal Flow ◽  
Navier Stokes ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Aero Engine ◽  
Flow Effects ◽  
Development And Validation

This study refers to the development and validation of a Three Dimensional (3D) Vortex Lattice Method (VLM) to be used for internal flow case studies and more precisely aero-engine intake simulation. It examines the quantitative and qualitative response of the method to a convergent – divergent intake, produced as a surface of revolution of the CFM56-5B2 upper lip geometry. The study was carried out for three different sections namely: Intake outlet, intake throat and intake inlet. Moreover five different settings of Angle Of Attack (AOA) were considered. The VLM was based on an existing code. It was modified to accommodate internal flow effects and match, as closely as possible, the boundary conditions set by the Reynolds Average Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) simulation. In the context of this study, Vortex Lattice-derived average values velocity profiles were compared against RANS CFD results.

Unsteady aerodynamics investigation of deploying tandem-wing with different methods

2018 ◽  
Vol 233 (10) ◽  
pp. 3714-3733 ◽  
Author(s):  
Hao Cheng ◽  
Hua Wang ◽  
Qingli Shi ◽  
Mengying Zhang
Keyword(s):  
Fore Wing ◽  
Vortex Lattice ◽  
Lift Coefficient ◽  
Unsteady Aerodynamics ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Induced Drag ◽  
Lifting Line ◽  
Lifting Line Method ◽  
Unsteady Lift

In the rapidly deploying process of the unmanned aerial vehicle with folding wings, the aerodynamic characteristics could be largely different owing to the effects of deformation rate and the aerodynamic interference. The investigation on the unsteady aerodynamics is of great significance for the stability analysis and control design. The lifting-line method and the vortex-lattice method are improved to calculate the unsteady aerodynamics in the morphing stage. It is validated that the vortex-lattice method predicts the unsteady lift coefficient more appropriately than the lifting-line method. Different tandem wing configurations with deployable wings are simulated with different deformation rates during the morphing stage by the vortex-lattice method. As results indicated, the unsteady lift coefficient and the induced drag of the fore wing rise with the deformation rate increasing, but it is reversed for the hind wing. Additionally, the unsteady lift coefficient of the tandem wing configuration performs well with a larger stagger, a larger magnitude of the gap and a larger wingspan of the fore wing; however, the total induced drag has a larger value for the configuration that the two lifting surfaces with the same wingspans are closer to each other.

A Vortex Model of the Darrieus Turbine: An Analytical and Experimental Study

1979 ◽  
Vol 101 (4) ◽  
pp. 500-505 ◽  
Author(s):  
J. H. Strickland ◽  
B. T. Webster ◽  
T. Nguyen
Keyword(s):  
Experimental Study ◽  
Prediction Model ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Wake Flow ◽  
Two Dimensional ◽  
Lattice Method ◽  
Near Wake ◽  
Vortex Lattice Method ◽  
Vortex Model

An aerodynamic prediction model has been formulated for two- and three-dimensional Darrieus turbines using a vortex lattice method of analysis. Experiments were conducted on a series of two-dimensional rotor configurations in a water tow tank. The agreement between analysis and experiment was in general found to be good. This model should allow one to make accurate predictions of instantaneous aerodynamic blade forces and to characterize the near wake flow behind the rotor.

scholarly journals Aerodynamic Reduced-Order Modeling without Static Correction Requirement Based on Body Vortices

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Suwin Sleesongsom ◽  
Sujin Bureerat
Keyword(s):  
Present Method ◽  
Vortex Lattice ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Reduced Order Modeling ◽  
Reduced Order Models ◽  
Lattice Method ◽  
Reduced Order ◽  
Vortex Lattice Method ◽  
Static Correction

The objective of this research is to propose a new reduced-order modeling method. This approach is based on fluid eigenmodes and body vortices without using static correction. The vortex lattice method (VLM) is used to analyze unsteady flows over two-dimensional airfoil and three-dimensional wing. Eigenanalysis and reduced-order modeling are performed using a conventional method with static correction and an unconventional one without the static correction. Numerical examples are proposed to demonstrate the performance of the present method. The results show that the new method can be considered an alternative way to perform the reduced-order models of unsteady flow.

scholarly journals Induced-Drag Calculations in the Unsteady Vortex Lattice Method

AIAA Journal ◽  
2013 ◽  
Vol 51 (7) ◽  
pp. 1775-1779 ◽  
Author(s):  
Robert J. S. Simpson ◽  
Rafael Palacios ◽  
Joseba Murua
Keyword(s):  
Vortex Lattice ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Induced Drag

Prediction of Non-Axisymmetric Effective Wake by a Three-Dimensional Euler Solver

2001 ◽  
Vol 45 (01) ◽  
pp. 13-33
Author(s):  
Jin-Keun Choi ◽  
Spyros A. Kinnas
Keyword(s):  
Vortex Lattice ◽  
Three Dimensional ◽  
Lattice Method ◽  
Vortex Lattice Method ◽  
Actuator Disk ◽  
Finite Volume Approach ◽  
Euler Solver ◽  
Effective Wake ◽  
Total Velocity ◽  
Surface Vortex

A fully three-dimensional Euler solver, based on a finite volume approach, is developed and applied to the prediction of the effective wake for propellers subject to non-axisymmetric inflows. The method is coupled with an existing lifting-surface vortex-lattice method for the analysis of unsteady cavitating propeller flows. The results are validated against analytical solutions from actuator disk theory. The effect of the grid parameters on the results (circumferential average and amplitudes of harmonics of the predicted effective wake) is found to be very weak. The predicted total velocity field correlates very well with that measured in propeller experiments.

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