Self-Propelling Vehicle CFD for Velocity and Stability Prediction

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Solution Overview

Problem

Current automotive design processes lack the ability to simulate the dynamics of moving vehicles, particularly in predicting vehicle velocity and stability based on engine load, which is crucial for aerodynamic design and efficiency, as they typically rely on stationary vehicle simulations and physical prototypes.

Innovation Solution

The implementation of a constraint-based immersed boundary method for computational fluid dynamics (CFD) that allows for the simulation of self-propelling vehicles, enabling the prediction of translational and rotational velocities and detailed airflow analysis, thereby addressing the limitations of existing CFD tools by modeling vehicles as rigid bodies within a fluid domain and using adaptive mesh refinement and detached eddy simulation techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If stationary vehicle simulations are used for aerodynamic design, then computational simplicity is maintained, but the ability to predict vehicle velocity and stability based on engine load is lost

Engineering Contradiction:
Improveprediction accuracy of vehicle velocity and stabilityVSAvoidsimulation model complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from stationary to dynamic simulation by introducing time-dependent vehicle motion. The simulation model now accounts for vehicle acceleration, velocity changes, and positional movements through the fluid domain, enabling prediction of vehicle velocity and stability under varying engine load conditions while maintaining computational feasibility through structured grid approaches.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If physical prototypes are used for aerodynamic testing, then measurement accuracy is improved, but development time and cost increase

Engineering Contradiction:
Improveaerodynamic measurement accuracyVSAvoiddevelopment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent creates a virtual copy of the physical vehicle through detailed computational geometry modeling. This digital replica allows for accurate aerodynamic measurements including pressure distributions, flow patterns, and force calculations without requiring physical prototypes. The simulation reproduces real-world aerodynamic behavior while eliminating the time-consuming iterative process of building and testing physical models.

Inventive Principle:
Principle #26Copying

3Measurement precision

If high-fidelity CFD simulations are implemented, then aerodynamic prediction accuracy is improved, but computational cost increases

Engineering Contradiction:
Improveaerodynamic drag prediction accuracyVSAvoidcomputational energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements adaptive parameter adjustment where grid resolution, time step size, and turbulence model complexity are dynamically modified based on flow conditions and regions of interest. High-resolution grids are applied only where necessary (e.g., boundary layers, wake regions) while coarser grids are used in low-gradient areas, maintaining accuracy for drag prediction while reducing overall computational energy consumption.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If adaptive mesh refinement is used for moving vehicles, then simulation accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improvegrid resolution accuracyVSAvoidmesh generation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The computational domain is divided into multiple structured grid zones with different resolution levels. Adaptive mesh refinement is applied selectively to specific regions such as the vehicle boundary layer, wake region, and areas with high gradient flow, while maintaining coarser grids in low-interest areas. This segmented approach achieves high local accuracy without requiring fine resolution throughout the entire domain, reducing overall computational complexity.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables efficient and accurate simulation of vehicle motion and aerodynamics, reducing the need for physical prototypes, improving design efficiency, and providing insights into stability and drag reduction strategies, especially under fluctuating wind conditions.

Implementation Method 1

The constraint-based immersed boundary method for computational fluid dynamics (CFD) that allows for the simulation of self-propelling vehicles

Methodology Applied
Scientific EffectNavier-Stokes equations:

Implementation Method 2

using adaptive mesh refinement and detached eddy simulation techniques

Methodology Applied
Scientific EffectAdaptive mesh refinement:

Implementation Method 3

detached eddy simulation techniques

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 4

providing insights into stability and drag reduction strategies

Methodology Applied
Scientific EffectDrag: Drag

Data Source

PatentUS11281826B2Systems and methods for computational simulation of self-propelling vehicles for aerodynamic design
Publication Date: 2022.03.22 NORTHWESTERN UNIV
  • US11281826B2 patent drawing
  • US11281826B2 patent drawing
  • US11281826B2 patent drawing

AI summary

Systems, methods, and computer readable media to simulate and predict translational and/or rotational velocity of a moving vehicle based on a determination of engine load for the vehicle are disclosed. An example vehicle motion simulator system includes a speed and stability predictor to simulate and predict a translational and rotational velocity of a moving vehicle based on a determination of engine load for the moving vehicle characterized by the speed and stability predictor. The example speed and stability predictor to execute instructions to at least: compute a nearest wall distance for the moving vehicle in an environment; solve an eddy viscosity for the environment; solve a flow velocity for the environment; and determine vehicle motion to characterize a speed and stability of the moving vehicle based on the wall distance, eddy viscosity, and flow velocity.