The Flow Topology of the Ahmed Body in Cross-Wind

The Flow Topology of the Ahmed Body in Cross-Wind: An Experimental Investigation by means of Robotic Volumetric PIV

Giaquinta, Daniele (TU Delft Aerospace Engineering; TU Delft Aerodynamics, Wind Energy & Propulsion)

Sciacchitano, Andrea (mentor)
Scarano, Fulvio (graduation committee)
Eitelberg, Georg (graduation committee)
van Raemdonck, Gandert (graduation committee)

Delft University of Technology

Aerospace Engineering | Aerodynamics and Wind Energy

2018-03-23

The near wake of the Ahmed reference body in the presence of steady cross-wind is investigated experimentally by means of large-scale three-dimensional Particle Image Velocimetry (PIV). A novel experimental technique is employed which exploits coaxial imaging and illumination while relying on Helium Filled Soap Bubble (HFSB) seeding as well as on robotic actuation. A 50% replica of the Ahmed body with a 25° slant angle is, therefore, considered in different configurations, among which the headwind condition and two different yaw angles, β1 = +4° and β2 = +8°. A height-based Reynolds number of 1.15 × 10^5 is chosen together with an airspeed of 12 m/s and the Open Jet Facility (OJF) Wind Tunnel of TU Delft is employed to perform the experiment.The relevance of the proposed work lies in the importance of experimental data concerning the Ahmed reference body as well as in the shortage of it with respect to the cross-wind case. The Ahmed body, indeed, once studied to improve the understanding of the flow field generated by road vehicles and to achieve a substantial drag reduction, is nowadays used as Computational Fluid Dynamics (CFD) benchmark and validation tool for automotive applications.To the best of the author’s knowledge, no work is present in the literature which investigates the flow field around the Ahmed body by means of three-dimensional quantitative measurement techniques such as the employed robotic volumetric velocimetry. The proposed study is, therefore, expected to be a significant contribution to the body of knowledge, supplying new valuable data to be used for validation purposes and to inspire future works.

Ahmed body
bluff body
cross-wind
flow topology
wake
C-pillar vortex
PIV
PTV
CVV
robotic volumetric PIV
experimental

http://resolver.tudelft.nl/uuid:27b75b3f-8b4d-4977-82ee-e531fd986839

Student theses

master thesis

© 2018 Daniele Giaquinta