The Proper Orthogonal and Dynamic Mode Decomposition of wake behind a Fastback DrivAer Model
2022-01-1086
03/29/2022
- Event
- Content
- The aerodynamic design optimization of a ground vehicle highly depends on the wake region behind it. Vehicle's wake and its instability have a major contribution to the drag, lift, and side forces experienced by the vehicle. In this paper, we investigate numerically the dynamic characteristics of wake downstream of a realistic generic car model, DrivAer, at a Reynolds number Re=4.87E06. Two methods, Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) are applied to symmetric and asymmetric 2D planes at y=0 and 0.5 H to decompose the unsteady wake to its major dynamic modes. We simulated the flow field using the turbulence model URANS/IDDES then applied POD and DMD on streamwise and spanwise velocity components and the pressure fields. Wake dynamic mode analysis enables us to capture different modes and their contributions to the kinetic energy distribution within the region of interest. For DrivAer geometry, at high Reynolds number, we observed quasi-steady wake deviation, vortex shedding, and bubble pumping as the most dominant fluctuation modes. These findings would help us characterize the average and principal unsteady features of wake in order to control the flow field and accurately predict the aerodynamic characteristics of a ground vehicle.
- Citation
- Ahani, H., Uddin, M., and Nielsen, J., "The Proper Orthogonal and Dynamic Mode Decomposition of wake behind a Fastback DrivAer Model," SAE Technical Paper 2022-01-1086, 2022, .