Composite material structure optimization design and aeroelastic analysis on forward swept wing

2018 ◽  
Vol 233 (13) ◽  
pp. 4679-4695 ◽  
Author(s):  
Xue Rongrong ◽  
Ye Zhengyin ◽  
Ye Kun ◽  
Wang Gang
Keyword(s):  
Optimization Design ◽  
Navier Stokes ◽  
Aerodynamic Load ◽  
Material Structure ◽  
Swept Wing ◽  
Aeroelastic Tailoring ◽  
Aeroelastic Analysis ◽  
Material Orientation ◽  
Weight Penalty ◽  
Divergence Problem

The static aeroelastic torsion divergence problem is the main obstacle to bring forward swept wing into massive applications. The aeroelastic tailoring technique-based radial basis function neural networks (RBFNNs) and genetic algorithm (GA) optimization in MATLAB considering the material orientation, thickness, and lay-up are elucidated in the present work. RBFNNs are used to build a surrogate model between the composite parameters and structure displacement, which is proved robust and accurate. Then an optimal structure is obtained by GA global search based on RBFNNs model with the weight constrain. The displacements of the forward swept wing caused by an approximate aerodynamic load are decreased 32.5% through finite element method (FEM) static structural analysis. The modal analysis illustrates that the first mode frequency increases by 33.0% and the second mode increases by 37.9%. A computational aeroelasticity approach is developed by in-house Hybrid Unstructured Reynolds-Averaged Navier-Stokes solver associating an open source FEM code – Calculix. The results of coupling calculations show effectiveness of aeroelastic tailoring optimization of composite forward swept wing without weight penalty. The results obtained demonstrate that for the forward swept wing, the most violent situation appears around Mach Number 1.0 where the aeroelastic tailoring optimization could decrease the torsion angle by nearly 70.0%. The torsion of forward swept wing will increase at subsonic and decrease at supersonic with the increase of velocity.

Modified Harmonic Balance Method for Nonlinear Aeroelastic Analysis of Two Degree-of-Freedom Airfoils in Supersonic Flow

2018 ◽  
Vol 18 (06) ◽  
pp. 1871006 ◽  
Author(s):  
Yaobin Niu ◽  
Zhongwei Wang
Keyword(s):  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Current Method ◽  
Degree Of Freedom ◽  
Balance Method ◽  
Aerodynamic Load ◽  
Nonlinear Aeroelasticity ◽  
Unsteady Aerodynamic ◽  
Aeroelastic Analysis ◽  
Two Degree Of Freedom

In this paper, a new modified harmonic balance method is presented for the nonlinear aeroelastic analysis of two degree-of-freedom airfoils. Using this method, the nonlinear problem is first translated into a minimization problem, and the Particle Swarm Optimization which has high calculation efficiency is adopted to solve the problem. The proposed method is used to solve the nonlinear aeroelastic behavior of supersonic airfoil, with the unsteady aerodynamic load evaluated by the piston theory. Three examples of nonlinear aeroelasticity with significantly different coefficients are prepared, in which the frequencies and amplitudes of the limit cycles are obtained. The results show that the present current method is computationally more efficient.

Design and characteristic analysis of an aerostatic decoupling table for microelectronic packaging

2017 ◽  
Vol 232 (6) ◽  
pp. 1079-1090 ◽  
Author(s):  
Cunman Liang ◽  
Fujun Wang ◽  
Qingguo Yang ◽  
Yanling Tian ◽  
Xingyu Zhao ◽  
...  
Keyword(s):  
High Precision ◽  
Optimization Design ◽  
Micro Electro Mechanical System ◽  
Navier Stokes ◽  
Orifice Diameter ◽  
Precision Positioning ◽  
Characteristic Analysis ◽  
Navier Stokes Equation ◽  
Decoupling Mechanism ◽  
Aerostatic Bearings

This paper presents a novel 2-DOF XY table with high-precision positioning to improve the efficiency and precision of micro-electro-mechanical system packaging. The XY table, which is supported by aerostatic bearings to realize high-precision positioning motion, is directly driven by two linear voice coil actuators. The motion decoupling between the X-and Y-axes is realized through a novel aerostatic decoupling mechanism, by which the mass and inertia of motion parts are reduced significantly. The mechanical structure of the XY table is designed and the decoupling mechanism is studied. Based on the Navier–Stokes equation, the influences of orifice diameter and lubrication gap on the carrying capacity as well the static stiffness of the aerostatic bearings are analyzed. The parameters of the aerostatic bearings are determined by single factor method. Using the finite element method, the static, modal, and transient analyses of the developed positioning table are carried out to investigate the characteristics of the positioning table. The results show that the positioning table provides good performance and can also provide important information for the optimization design and control of this kind of the positioning table.

Phase-Lagged Boundary Condition Methods for Aeroelastic Analysis of Turbomachines: A Comparative Study

1999 ◽  
Author(s):  
R. Srivastava ◽  
Milind A. Bakhle ◽  
Theo G. Keith ◽  
G. L. Stefko
Keyword(s):  
Boundary Condition ◽  
Comparative Study ◽  
Decomposition Method ◽  
Decomposition Methods ◽  
Navier Stokes ◽  
Fourier Decomposition ◽  
Computational Costs ◽  
Aeroelastic Analysis ◽  
Study Results ◽  
Time Marching

In the present work a comparative study of phase-lagged boundary condition methods is carried out. The relative merits and advantages of time-shifted and the Fourier decomposition methods are compared. Both methods are implemented in a time marching Euler/Navier-Stokes solver and are applied to a flat plate helical fan with harmonically oscillating blades to perform the study. Results were obtained for subsonic as well as supersonic inflows. Results for subsonic inflow showed good comparisons with published results and between the two methods along with comparable computational costs. For the supersonic inflow, despite the presence of shocks at the periodic boundary results from both the methods compared well, however, Fourier decomposition method was computationally more expensive. For linear flowfield Fourier decomposition method is best suited, especially for work-station environment. The time-shifted method is better suited for CRAY category of computers where fast input-output devices are available.

Influence of Rotor Blade Fillets on Aerodynamic Performance of Turbine Stage

2010 ◽  
Author(s):  
Yan Shi ◽  
Jun Li ◽  
Zhenping Feng
Keyword(s):  
Secondary Flow ◽  
Rotor Blade ◽  
Stokes Equations ◽  
Leading Edge ◽  
Navier Stokes ◽  
Aerodynamic Load ◽  
Main Stream ◽  
Shape Parameters ◽  
Turbine Stage ◽  
A Minor

In this paper, steady and unsteady flow simulations were performed to investigate the influence of rotor fillet on the performance of turbine stage, based on 3D compressible Navier-Stokes equations closed with the Spalart-Allmaras turbulence model. The profile of Aachen turbine was employed and the fillet modeled by two shape parameters was placed at the junctions between the rotor blade and the endwalls (at both tip and hub). Based on the comparisons of the efficiency and the flow rate of turbine stage among the cases with different fillet shapes, the roles of two shape parameters were evaluated. To understand the mechanism of the rotor fillet influence on the flow field, the aerodynamic load, secondary flow and loss were analyzed and compared between the cases with and without the rotor fillet. It is found that the fillet is capable of restraining the flow separation near the leading edge of the rotor blade while inducing the displacement of the flow from the endwalls towards the mid-span, which enhances the loss generated by the interaction between the secondary flow and the main stream. Consequently, associated with the distribution of the loss at the outlet of the turbine stage, the best clocking position near the endwalls for the downstream blade moves about 10%∼20% of rotor pitch in the direction of rotor rotation. Therefore, the shape of the fillet in the rotor blade should be especially controlled in the process of the rotor design and manufacture, even though it is a minor part in the turbomachine.

scholarly journals Multidisciplinary optimization of an NLF forward swept wing in combination with aeroelastic tailoring using CFRP

2017 ◽  
Vol 8 (4) ◽  
pp. 673-690 ◽  
Author(s):  
Tobias Wunderlich ◽  
Sascha Dähne ◽  
Lars Heinrich ◽  
Lars Reimer
Keyword(s):  
Multidisciplinary Optimization ◽  
Swept Wing ◽  
Aeroelastic Tailoring

Modeling and Analysis of Main Flow–Shroud Leakage Flow Interaction in LP Turbines

2006 ◽  
Author(s):  
Jochen Gier ◽  
Karl Engel ◽  
Bertram Stubert ◽  
Ralf Wittmaack
Keyword(s):  
Main Flow ◽  
Navier Stokes ◽  
Aerodynamic Load ◽  
Leakage Flow ◽  
Modeling And Analysis ◽  
Simplified Approach ◽  
Leakage Flows ◽  
Flow Phenomena ◽  
Flow Effects ◽  
The Impact

Endwall losses significantly contribute to the overall losses in modern turbomachinery, especially when aerodynamic load and pressure ratios are increased. In turbines with shrouded airfoils a large portion of these losses are generated by the leakage flow across the shroud clearance. For the design of modern jet engine turbines it becomes increasingly important to include the impact of shroud leakage flows in the aerodynamic design. There are two main aspects connected to this issue. The first aspect is to optimize the cavity flow and its interaction with the main flow. The second aspect is to perform the airfoil design with boundary conditions, which include the shroud leakage flow effects. In comparison to the simplified approach of neglecting the real endwall geometry and leakage flow this should enable the designer to produce improved airfoils for the entire span. In order to address the second aspect of supporting the airfoil design with improved shroud leakage consideration within the airfoil design process, an efficient procedure for modeling the shroud leakage flow has been implemented into the design Navier-Stokes code. The intention is to model the major leakage flow phenomena without the necessity of pre-defining all details of the shroud geometry. In the paper the results of this model are compared to conventional computations, computations with mesh-resolved cavities and experimental data. The differences are discussed and the impact of certain configuration aspects are analyzed.

Generalizing Prediction of Bluff Body Aerodynamic Load Maps

2015 ◽  
Author(s):  
Sorin Pirau ◽  
Brandon Liberi ◽  
Natasha Barbely ◽  
Narayanan Komerath
Keyword(s):  
Aspect Ratio ◽  
Bluff Body ◽  
Navier Stokes ◽  
Gradual Transition ◽  
Aerodynamic Load ◽  
Rotation Method ◽  
Continuous Rotation ◽  
Rate Effects ◽  
Body Shapes ◽  
Definition Of

The Continuous Rotation method enables efficient definition of all aerodynamic load components on bodies of arbitrary shape for arbitrary attitudes. This is applied to several bluff body shapes including cylinders, a cuboid, a flat plate and a porous box. Rate effects and unsteadiness are shown to be negligible using a cylinder of aspect ratio 1. The genesis of the side force on the yawed cylinder, and the differences between rough and smooth cylinders, are derived from comparisons between experiments and diagnostic computations with an unsteady Navier-Stokes solver. Interpolating Fourier coefficients of the azimuthal load variation appears to be viable to generalize loads on cylinders of varying aspect ratio. A large variation is seen for aspect ratio 0.5 to 1, with a more gradual transition to ‘high aspect ratio’ features beyond aspect ratio 2.

scholarly journals Multi-objective aerodynamic optimization of flying-wing configuration based on adjoint method

2021 ◽  
Vol 39 (4) ◽  
pp. 753-760
Author(s):  
Xiaodong Liu ◽  
Peiliang Zhang ◽  
Guanghong He ◽  
Yongen Wang ◽  
Xudong Yang
Keyword(s):  
Optimization Design ◽  
Adjoint Method ◽  
Stokes Equations ◽  
Design Method ◽  
Adjoint Equation ◽  
Geometric Constraints ◽  
Navier Stokes ◽  
Aerodynamic Design ◽  
Aerodynamic Optimization ◽  
Multi Objective

In order to solve the multi-objective multi-constraint design in aerodynamic design of flying wing, the aerodynamic optimization design based on the adjoint method is studied. In terms of the principle of the adjoint equation, the boundary conditions and the gradient equations are derived. The Navier-Stokes equations and adjoint aerodynamic optimization design method are adopted, the optimization design of the transonic drag reduction for the two different aspect ratio of the flying wing configurations is carried out. The results of the optimization design are as follows: Under the condition of satisfying the aerodynamic and geometric constraints, the transonic shock resistance of the flying wing is weakened to a great extent, which proves that the developed method has high optimization efficiency and good optimization effect in the multi-objective multi-constraint aerodynamic design of the flying wing.

scholarly journals Aeroelastic Analysis of a Typical Section using Euler and Navier-Stokes Mesh-less Method

2016 ◽  
Vol 23 (1) ◽  
pp. 194-205
Author(s):  
S. Sattarzadeh ◽  
A. Jahangirian ◽  
H. Shahverdi
Keyword(s):  
Navier Stokes ◽  
Aeroelastic Analysis ◽  
Mesh Less
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