An Automated Shape Optimization Procedure for Drag Reduction of Ground Vehicles

Abstract A robust and automatic shape optimization procedure is presented in this paper, which incorporates recent developments in the field of computer-aided design (CAD) of mechanical structures, such as geometric modelling, automatic selection of independent design variables, sensitivity analysis using reliable mesh perturbation schemes, error estimation and adaptive mesh refinement. A numerical example is given to show the efficiency of the procedure.

Download Full-text

Aerodynamic Drag Reduction Investigation for a Simplified Road Vehicle Using Plasma Flow Control

Volume 1A, Symposia: Turbomachinery Flow Simulation and Optimization; Applications in CFD; Bio-Inspired and Bio-Medical Fluid Mechanics; CFD Verification and Validation; Development and Applications of Immersed Boundary Methods; DNS, LES and Hybrid RANS/LES Methods; Fluid Machinery; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Active Fluid Dynamics and Flow Control — Theory, Experiments and Implementation ◽

10.1115/fedsm2016-7927 ◽

2016 ◽

Author(s):

Bahram Khalighi ◽

Joanna Ho ◽

John Cooney ◽

Brian Neiswander ◽

Thomas C. Corke ◽

...

Keyword(s):

Drag Reduction ◽

Flow Control ◽

Plasma Flow ◽

Aerodynamic Drag ◽

Force Balance ◽

Plasma Actuators ◽

Ground Vehicles ◽

Mean Velocity ◽

Local Flow ◽

Plasma Flow Control

The effect of plasma flow control on reducing aerodynamic drag for ground vehicles is investigated. The experiments were carried out for a simplified ground vehicle using single dielectric barrier discharge (SDBD) plasma actuators. The plasma actuators were designed to alter the flow structure in the wake region behind the vehicle. The Ahmed body was modified to allow eight different vehicle geometries (with backlight or slant angles of 0° and 35°). Each of these were further modified by rounding the edges with different radii. Flow visualizations such as particle streams and surface oil were used to quantify features of the local flow field. The drag on the models was measured using a force balance as well as by integrating the mean velocity profiles in the model wakes. The results indicated that flow modifications needed to be applied symmetrically (upper to lower and/or side to side). This was demonstrated with the 0° backlight angle (square-back) that had all four side-corners rounded. Plasma actuators were applied to all four of the rounded edges to enhance the ability to direct the flow into the wake. Wake measurements showed that steady actuation at a fixed actuator voltage reduced the drag by an average of 20% at the lower velocities (below 15 m/s) and by 3% at the highest velocity tested (20 m/s). Model constraints prevented increasing the plasma actuator voltage that was needed to maintain the higher drag reduction observed at the lower speeds.

Download Full-text

Robust Shape Optimization of Uncertain Dense Gas Flows Through a Plane Turbine Cascade

ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D ◽

10.1115/ajk2011-05007 ◽

2011 ◽

Cited By ~ 2

Author(s):

Samuel J. Hercus ◽

Paola Cinnella

Keyword(s):

Robust Optimization ◽

Shape Optimization ◽

Flow Behavior ◽

Computational Cost ◽

Optimization Procedure ◽

System Stability ◽

Dense Gas ◽

Turbine Cascade ◽

The Mean ◽

Inlet Conditions

A robust shape optimization procedure based on a multi-objective genetic algorithm coupled to a non-intrusive uncertainty quantification analysis was applied to a transonic inviscid flow of a dense gas over a plane turbine cascade. The goal was to simultaneously improve the mean turbine performance and the system stability under fluctuating thermodynamic inlet conditions. Despite an elevated computational cost, the optimization procedure was capable of generating a Pareto front of turbine geometries which improved the mean isentropic turbine efficiency μ(ηs) over the baseline profile, while limiting the solution variability in terms of the coefficient of variation of the power output CV(P2D). In addition to demonstrating an excellent parallel scalability over 1600 processors, the robust optimization revealed that variability of CV(P2D) depends more on the variation of inlet conditions than turbine geometry. A posteriori stochastic analyses on selected optimized turbine geometries allowed an investigation of flow behavior variability, as well as propositions for the improved selection of robust optimization cost criteria in future simulations.

Download Full-text

City Car Drag Reduction by Means of Shape Optimization and Add-On Devices

Advances in Mechanism and Machine Science - Mechanisms and Machine Science ◽

10.1007/978-3-030-20131-9_367 ◽

2019 ◽

pp. 3721-3730 ◽

Cited By ~ 2

Author(s):

A. Ferraris ◽

A. G. Airale ◽

D. Berti Polato ◽

A. Messana ◽

S. Xu ◽

...

Keyword(s):

Shape Optimization ◽

Drag Reduction

Download Full-text

Shape Optimization Procedure of Interior Permanent Magnet Motors Considering Carrier Harmonic Losses Caused by Inverters

IEEE Transactions on Magnetics ◽

10.1109/tmag.2017.2758444 ◽

2018 ◽

Vol 54 (3) ◽

pp. 1-4 ◽

Cited By ~ 3

Author(s):

Katsumi Yamazaki ◽

Yusuke Togashi

Keyword(s):

Shape Optimization ◽

Permanent Magnet ◽

Optimization Procedure ◽

Permanent Magnet Motors ◽

Interior Permanent Magnet

Download Full-text

An Energy Formulation for Parametric Size and Shape Optimization of Compliant Mechanisms

Journal of Mechanical Design ◽

10.1115/1.2829448 ◽

1999 ◽

Vol 121 (2) ◽

pp. 229-234 ◽

Cited By ~ 91

Author(s):

J. A. Hetrick ◽

S. Kota

Keyword(s):

Shape Optimization ◽

Compliant Mechanisms ◽

Compliant Mechanism ◽

Optimization Procedure ◽

Stress Constraints ◽

Optimization Techniques ◽

Mechanical Transmission ◽

Dimensional Synthesis ◽

Size And Shape ◽

Mechanical Devices

Compliant mechanisms are jointless mechanical devices that take advantage of elastic deformation to achieve a force or motion transformation. An important step toward automated design of compliant mechanisms has been the development of topology optimization techniques. The next logical step is to incorporate size and shape optimization to perform dimensional synthesis of the mechanism while simultaneously considering practical design specifications such as kinematic and stress constraints. An improved objective formulation based on maximizing the energy throughput of a linear static compliant mechanism is developed considering specific force and displacement operational requirements. Parametric finite element beam models are used to perform the size and shape optimization. This technique allows stress constraints to limit the maximum stress in the mechanism. In addition, constraints which restrict the kinematics of the mechanism are successfully applied to the optimization problem. Resulting optimized mechanisms exhibit efficient mechanical transmission and meet kinematic and stress requirements. Several examples are given to demonstrate the effectiveness of the optimization procedure.

Download Full-text

Aerodynamic Optimization Design of Airfoil Based on Directly Manipulated FFD Technique

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.390.121 ◽

2013 ◽

Vol 390 ◽

pp. 121-128 ◽

Cited By ~ 1

Author(s):

Jun Qiang Bai ◽

Song Chen

Keyword(s):

Shape Optimization ◽

Drag Reduction ◽

Optimization Design ◽

High Order ◽

Control Points ◽

Aerodynamic Shape Optimization ◽

Aerodynamic Optimization ◽

Aerodynamic Shape ◽

Design Variables ◽

Geometrical Constraints

The method of applying direct manipulated FFD (DFFD) technique into aerodynamic shape optimization has been proposed and researched. Due to the disadvantage of the original FFD method within which the geometrical manipulation is not direct and intuitive, the DFFD approach has been developed by solving each displacement of the FFD control points with some specified geometry points movements, so that the deformation of the target geometry could be directly manipulated. Besides, it has been illustrated that by DFFD method a relatively small number of design variables together with high order FFD control frame could be accomplished. The study cases has shown that applying this method in aerodynamic shape optimization of airfoil for drag reduction is of good feasibility and result, and could be coupled with effective geometrical constraints like airfoil thickness.

Download Full-text