Evolution Measurement Ltd. - PRODUCT NEWS


Motor Sport Aerodynamic Pressure Scanning – The Winning Formula


The Application:

Race car aerodynamic optimisation continues to become more important in the search for performance advantage. A major part of a team ’s budget i s invested in enhancing and improving the aerodynamic performance of the car and a large team of aerodynamic specialists and facilities are employed in achieving this. Aerodynamic efficiency is a major contributor to a winning car. It is often said that a reduction in drag is less costly and easier to achieve than a weight reduction or a power increase. It is paradoxically challenging for the engineer to attain huge levels of downforce to enhance cornering performance without compromising car forward speed by increasing drag.

Stringent regulations governing car shapes and sizes leaves the aerodynamicist considering every part in order to reduce drag and gain competitive advantage. Front and rear aerofoils, or wings, together with the bodywork surface push the car down to the road surface. Under the car, complex venturi shapes increase air velocity, creating a low-pressure “suction ” effect, with minimal cost of drag.

Winglets and other devices are fitted, in addition to the front and rear wings, to condition the flow for downstream aerodynamics, or directly generate downforce effects themselves.

This leads to highly-creative design shapes and ever-more complex air flow analysis. CFD
(Computational Fluid Dynamics) becomes the prime tool for calculating airflow performance, but this is not enough. The data must be validated with extensive Wind Tunnel testing, as well as on-car testing, where possible. These three major forms of testing triangulate to gather useful data for analysis.

Where wind tunnel testing is utilised, a highly-detailed scale model (usually 60% scale) is constructed representing the full-size car. The model is installed in the wind tunnel, on a rolling road, to simulate moving ground effects, and subjected to extended testing over a wide range of wind velocities and directions, often up to 100 m/s. Data is gathered from numerous locations on the model to map the overall aero performance and identify any areas that require further analysis or evaluation. The model is supported from a multi-axis balance which measures the drag forces on the model very accurately.

The Measurement Challenge:
Since the sport’s ruling body limits the amount of wind t unnel time allowed, the challenge is to collect accurate meaningful data and make every second of “wind -on ” test-time count. The challenge for the engineer is to gather as much data as possible in the available time and to be able to quickly develop modifications to the model to install and validate improvements.

Typical models are fitted with numerous small pressure tappings that allow the localised pressure to be measured at a multitude (often many hundreds) of points on the aerodynamic surfaces. These tubes connect directly to the in-model pressure scanners for conversion to pressure measurements which are then time-stamped, synchronised and communicated to the computer systems via Ethernet or similar communications for mapping and further analysis. Tubing lengths should be kept as short as possible, whilst striving to collect data from the furthest model extremities. Similarly, finding space
for the pressure scanners is usually a challenge, so manufacturers, like Scanivalve, strive to create smaller, more space-efficient solutions. Data collection rate is also a challenge, to ensure that as many measurements as possible, often thousands per channel per second, are gathered in the available time.

Typical Users :
Vehicle development and race teams often run their own wind tunnels, but some sub-contract the testing programme to an external wind tunnel operator, who may also provide design consultancy, in addition to gathering and presenting the data from the model test runs.

The Solution
Scanivalve MPS 4264 Pressure Scanner excels in this application

* Compact, high performance Pressure Scanner
* Dedicated sensor for each channel (up to 64 channels)
* High Accuracy temperature compensated sensors
* Network-ready Ethernet for quick system integration
* Fast data collection up to 2500 samples/channel/second
* Dynamic Zero Correction for unmatched sensor stability
* IEEE1588-2008v2 PTP compatibility
* Removable headers for installation flexibility
* Simple LabVIEW integration

Multiple Scanivalve MPS 4264 pressure scanners are mounted within the model to collect the huge amount of data being generated under test. Ethernet outputs and power supplies can be multiplexed through local Scanivalve hubs, further adding to the compactness of the solution, with one hub typically handling real-time synchronous data of over 500 live pressure measurements.

Even across a wide range of wind speeds, the pressures can remain quite low, so this requires scanners with high accuracy, repeatability and sensitivity. Scanivalve MPS is suitable for use as low as full scale ranges of 4 ” H 2O and up to 50 psi, with other custom ranges possible to suit all applications.

High-speed Ethernet data rates of up to 2500Hz/channel ,in “Fast Mode ”, maximise the amount of valuable data that can be gathered during a single test run. This data is collected in any common Engineering Unit, directly presenting the test engineers with meaningful data for analysis.

Removable headers on the scanner mean that 64 tubes may be conveniently connected before the scanner is installed in the tunnel and adds to the versatility of using one scanner on multiple models, avoiding unnecessary downtime during test periods. The headers can remain fitted to the model for Integration of the Scanivalve MPS is quick and simple. The integral web-server allows the scanner to be set up from a PC and further integrated into a LabVIEW package, avoiding the need for any separate
signal converters or marshalling cabinets.

In addition to a versatile range of high performance pressure scanners, Evolution Measurement offer the widest range of accessories including pressure tubulations, tubing and connectors that enable the test model to be commissioned very quickly and efficiently.

Download the datsheets >>
1 & 2

For more information, please contact:-

Evolution Measurement Ltd.
7 Regents Court, South Way,
Walworth Business Park Andover,
Hampshire SP10 5NX . UK
Telephone: +44 (0) 1264 316470

August 2017

Home - Search - Suppliers - Links - New Products - Catalogues - Magazines
Problem Page - Applications - How they work - Tech Tips - Training - Events