Reports de recerca
http://hdl.handle.net/2117/171505
2024-09-18T15:45:49ZExplicit dynamic analysis of thin membrane structures
http://hdl.handle.net/2117/172719
Explicit dynamic analysis of thin membrane structures
Flores Le Roux, Roberto Maurice; Ortega, Enrique; Oñate Ibáñez de Navarra, Eugenio
An explicit dynamic structural solver developed at CIMNE for the analysis of parachutes is presented. The canopy fabric has a negligible out-of-plane stiffness, therefore its numerical study presents important challenges. Both the large changes in geometry and the statically indeterminate character of the system are problematic from the numerical point of view. This report covers the reasons behind the particular choice of solution scheme as well as a detailed description of the underlying algorithm. Both the theoretical foundations of the method and details of implementation aiming at improving computational efficiency are given. Benchmark cases to assess the accuracy of the solution as well as examples of practical application showing the performance of the code are finally presented.
CIMNE Publicaciones nº 351
2019-11-20T06:25:33ZFlores Le Roux, Roberto MauriceOrtega, EnriqueOñate Ibáñez de Navarra, EugenioAn explicit dynamic structural solver developed at CIMNE for the analysis of parachutes is presented. The canopy fabric has a negligible out-of-plane stiffness, therefore its numerical study presents important challenges. Both the large changes in geometry and the statically indeterminate character of the system are problematic from the numerical point of view. This report covers the reasons behind the particular choice of solution scheme as well as a detailed description of the underlying algorithm. Both the theoretical foundations of the method and details of implementation aiming at improving computational efficiency are given. Benchmark cases to assess the accuracy of the solution as well as examples of practical application showing the performance of the code are finally presented.A 3D low-order panel method for unsteady aerodynamic problems
http://hdl.handle.net/2117/172220
A 3D low-order panel method for unsteady aerodynamic problems
Ortega, Enrique; Flores Le Roux, Roberto Maurice; Oñate Ibáñez de Navarra, Eugenio
An unsteady low-order panel method for three-dimensional subsonic analyses is presented. The method, which is based on well-established techniques in computational aerodynamics, is intended to achieve a cost-effective solution of unsteady flows around arbitrary aerodynamic configurations. This work has two main objectives. First, to relax geometry discretization requirements and, second, to simplify the treatment of problems in which the analysis configuration moves along specified flight paths and/or changes its geometry during the simulation. Following this aim, a time-marching solution procedure is adopted in conjunction with a free-wake model which avoids iterative solutions for wake shape and position. The suitability of the present approach for solving typical aerodynamic problems is illustrated by means of several numerical examples.
2019-11-12T11:11:02ZOrtega, EnriqueFlores Le Roux, Roberto MauriceOñate Ibáñez de Navarra, EugenioAn unsteady low-order panel method for three-dimensional subsonic analyses is presented. The method, which is based on well-established techniques in computational aerodynamics, is intended to achieve a cost-effective solution of unsteady flows around arbitrary aerodynamic configurations. This work has two main objectives. First, to relax geometry discretization requirements and, second, to simplify the treatment of problems in which the analysis configuration moves along specified flight paths and/or changes its geometry during the simulation. Following this aim, a time-marching solution procedure is adopted in conjunction with a free-wake model which avoids iterative solutions for wake shape and position. The suitability of the present approach for solving typical aerodynamic problems is illustrated by means of several numerical examples.A numerical investigation of wind tunnel model deformations caused by the twin-sting support system
http://hdl.handle.net/2117/172211
A numerical investigation of wind tunnel model deformations caused by the twin-sting support system
Flores Le Roux, Roberto Maurice; Ortega, Enrique; Oñate Ibáñez de Navarra, Eugenio
This work presents a wing deformation analysis of a twin-sting-mounted commercial aircraft model. Twin-sting arrangements minimize flow disturbances around the model fuselage and tail; on the other hand, they cause important changes in the flow field around the wing and also increase aerodynamic interference at the wing and aeroplastic effects on the wing. In some cases, these effects can alter the normal downwash developed behind the wing, modifying the flow pattern at the tail. Consequently, when tail aerodynamics is a major concern, this kind of support interference should be carefully evaluated. The methodology developed in this work employs an unstructured FEM-based flow solver for computing aerodynamic loads. These loads are then transferred to a finite element structural model in order to assess the geometrical deformation of the wing caused by the torsional moment exerted by the supporting mechanism. The analysis described involves there different twin-sting support configurations taking into account angle of attack variations and Mach numbers spanning from subsonic to high transonic ranges.
2019-11-12T10:10:40ZFlores Le Roux, Roberto MauriceOrtega, EnriqueOñate Ibáñez de Navarra, EugenioThis work presents a wing deformation analysis of a twin-sting-mounted commercial aircraft model. Twin-sting arrangements minimize flow disturbances around the model fuselage and tail; on the other hand, they cause important changes in the flow field around the wing and also increase aerodynamic interference at the wing and aeroplastic effects on the wing. In some cases, these effects can alter the normal downwash developed behind the wing, modifying the flow pattern at the tail. Consequently, when tail aerodynamics is a major concern, this kind of support interference should be carefully evaluated. The methodology developed in this work employs an unstructured FEM-based flow solver for computing aerodynamic loads. These loads are then transferred to a finite element structural model in order to assess the geometrical deformation of the wing caused by the torsional moment exerted by the supporting mechanism. The analysis described involves there different twin-sting support configurations taking into account angle of attack variations and Mach numbers spanning from subsonic to high transonic ranges.An edge-based solver for compressible flow
http://hdl.handle.net/2117/171504
An edge-based solver for compressible flow
Ortega, Enrique; Flores Le Roux, Roberto Maurice; Oñate Ibáñez de Navarra, Eugenio
An edge-based high-resolution scheme for the solution of the compressible Euler equations on unstructured finite elements grids is presented. The flow solver adopted in the present work is the approximate Riemann solver developed by Roe. A high-order spatial approximation is achieved by means of a piecewise linear reconstruction of the interface variables according to the MUSCL (Monotone Upstream-centered Schemes for Conservation Laws) formulation. Finally, non-linear limiters are introduced in order to prevent the generation of oscillations. The proposed approach corresponds with the methodology presented by Löhner in [1].
2019-11-05T06:44:03ZOrtega, EnriqueFlores Le Roux, Roberto MauriceOñate Ibáñez de Navarra, EugenioAn edge-based high-resolution scheme for the solution of the compressible Euler equations on unstructured finite elements grids is presented. The flow solver adopted in the present work is the approximate Riemann solver developed by Roe. A high-order spatial approximation is achieved by means of a piecewise linear reconstruction of the interface variables according to the MUSCL (Monotone Upstream-centered Schemes for Conservation Laws) formulation. Finally, non-linear limiters are introduced in order to prevent the generation of oscillations. The proposed approach corresponds with the methodology presented by Löhner in [1].