The aerodynamics of close running ground vehicles

Lead Research Organisation: University of Birmingham
Department Name: Civil Engineering

Abstract

In recent years the concept of driverless or autonomous road vehicles (AVs) has gained a great deal of technical respectability and most major manufacturers intend to bring a partially or fully autonomous vehicle to market within the next few years. Much progress has been made on a range of technologies relevant to this concept, including digital mapping, position recognition by lidar and radar systems and advanced vehicle to vehicle communications. There are a number of advantages for such vehicles over normal driver controlled vehicles in terms of safety, reliability, access for the disabled and increasing the efficiency of road use. The latter comes about primarily because such vehicles are able to drive closely together in platoon formation. This project is concerned with a technical area associated with platoon running. where to date only a restricted amount of experimental work has been carried out - that of the aerodynamics of vehicles travelling in platoons, and the nature of the flow field in and around platoons is not well understood. In particular the following aspects will be investigated.
a) The overall stability of vehicles travelling in the wake of other vehicles, particularly if there are organised coherent wake flow structures such as trailing vortices. These stability effects may be made more severe by the presence of slight cross winds that result in asymmetric and variable wakes, which can be expected to occur for the majority of the time.
b) Problems associated with exhaust pollutants can also be envisaged, as it is possible that pollutants may build up along the length of the platoon and not be released into the open atmosphere, and may, if the conditions are suitable, be ingested by vehicle power plant and ventilation systems.
c) Aerodynamic noise is an important design consideration for road vehicles, both in terms of passenger and driver comfort, and in terms of the overall effect of traffic on the surrounding environment. It is not clear how the use of platoon running of AVs will affect the internal and external propagation of aerodynamic vehicle noise.
In addition work is proposed to investigate a related problem - the aerodynamic aspects of trains running very closely together, an issue which has emerged from recent studies of high speed coupling and uncoupling operations.
This work will be carried out through physical and computational modelling. The physical modelling work will utilise the University of Birmingham moving model TRAIN Rig, which allows individual and platoons of vehicles to be propelled along a 150m long test track at speeds of up to 80m/s. The work will involve detailed measurements of pressure over the vehicles (such that aerodynamic forces can be calculated), and measurements of aerodynamic noise propagation from platoons and pollutant dispersion from platoons. The computational work will be carried out using conventional RANS techniques for a wide range of vehicle and platoon configurations, but also a smaller number of calculations using more sophisticated DES and LED methods to provide high quality unsteady flow information. Taken together, the physical modelling results and the CFD will enable a detailed understanding to be achieved of the aerodynamic behaviour of ground vehicles running closely together, which will be of considerable interest and importance to a variety of stakeholders.

Planned Impact

The major impact of the research for stakeholders will be as follows.
a) Manufacturers of autonomous vehicles - detailed information on drag, lift and vehicle stability for a range of vehicle types and spacings, information on pollution dispersion and noise levels within the different platoons.
b) Operators of transport systems using autonomous vehicles - guidance for design of AV control systems, information on the spread of noise and pollutants away from vehicle platoons.
c) Train operators interested in close running of vehicles - information on aerodynamic instability effects for trains running in close formation.
These benefits will be achieved through direct dissemination to key stakeholders who are project partners and serve on the project Steering Committee; through strong interaction with the Transport systems Catapult Centre - the UK transport innovation centre based in Milton Keynes; through dissemination seminars and a major final London based event; and through publication in academic and professional journals.
 
Description It has been found that the platoon has a significant effect of the aerodynamics of the vehicles in the platoon compared to an isolated vehicle. The research is ongoing and detailed of the finding will be clear closer to the end of the project.
Exploitation Route The steering group of the project consists of leading car manufacturers in the UK. The findings of the project are of a great important to their product development.
Sectors Energy,Environment,Transport

 
Description The non-academic impacts are only just beginning to develop, and can be expected to expand significantly in the next few years in terms of methodologies for measuring flows around model scale platoon and for the use of CFD. These methodologies will be of used by car and train manufacturers in vehicle design and in the train authorisation process.
First Year Of Impact 2018
Sector Transport
Impact Types Societal,Economic,Policy & public services

 
Description UKFN 
Organisation Loughborough University
Country United Kingdom 
Sector Academic/University 
PI Contribution We are an active member in the UK Fluid Network (UKFN). Hemida is a member of two special interest groups, Vehicle Aerodynamics and Urban Wind.
Collaborator Contribution Baker is the co-organizer of the vehicle aerodynamics SIG and Quinn is the co-organizer of the Urban wind SIG. Hemida is an active member of the two SIGs. In 2018, Hemida organized two meeting in Birmingham one for the Vehicle Aerodynamics and one for the Urban Wind SIG.
Impact Still ongoing
Start Year 2017
 
Description UKFN 
Organisation University of Bristol
Country United Kingdom 
Sector Academic/University 
PI Contribution We are an active member in the UK Fluid Network (UKFN). Hemida is a member of two special interest groups, Vehicle Aerodynamics and Urban Wind.
Collaborator Contribution Baker is the co-organizer of the vehicle aerodynamics SIG and Quinn is the co-organizer of the Urban wind SIG. Hemida is an active member of the two SIGs. In 2018, Hemida organized two meeting in Birmingham one for the Vehicle Aerodynamics and one for the Urban Wind SIG.
Impact Still ongoing
Start Year 2017
 
Description UKFN 
Organisation University of Manchester
Country United Kingdom 
Sector Academic/University 
PI Contribution We are an active member in the UK Fluid Network (UKFN). Hemida is a member of two special interest groups, Vehicle Aerodynamics and Urban Wind.
Collaborator Contribution Baker is the co-organizer of the vehicle aerodynamics SIG and Quinn is the co-organizer of the Urban wind SIG. Hemida is an active member of the two SIGs. In 2018, Hemida organized two meeting in Birmingham one for the Vehicle Aerodynamics and one for the Urban Wind SIG.
Impact Still ongoing
Start Year 2017
 
Description UKFN 
Organisation University of Southampton
Country United Kingdom 
Sector Academic/University 
PI Contribution We are an active member in the UK Fluid Network (UKFN). Hemida is a member of two special interest groups, Vehicle Aerodynamics and Urban Wind.
Collaborator Contribution Baker is the co-organizer of the vehicle aerodynamics SIG and Quinn is the co-organizer of the Urban wind SIG. Hemida is an active member of the two SIGs. In 2018, Hemida organized two meeting in Birmingham one for the Vehicle Aerodynamics and one for the Urban Wind SIG.
Impact Still ongoing
Start Year 2017
 
Description Eureca Conference, Malaysia 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact That was an invited keynote speech in Taylor University annual conference in Malaysia.
Year(s) Of Engagement Activity 2016
 
Description Key note speaker China 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Keynote speaker in the 2nd International Conference on Industrial Aerodynamics (ICIA), Qingdao, China.
Year(s) Of Engagement Activity 2017
 
Description Keynote London 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This was an invited keynote speech in the The Global Summit and Expo on Fluid Dynamics and Aerodynamics.
Year(s) Of Engagement Activity 2016
 
Description Organizing International conference 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact University of Birmingham has been chosen to host the 9th International Conference of Bluff Body Aerodynamics and Applications (BBAA), Birmingham, 2020. Hemida is the Chair of the conference.
Year(s) Of Engagement Activity 2018
 
Description Visiting Professor 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Undergraduate students
Results and Impact Dr Hemida was invited as a visiting professor at the Lanzhou university in China to deliver three lectures about train aerodynamics as part of their 60th anniversary of train aerodynamic division in the university. The audiences were a mix of academics, graduate and undergraduate students. The number of attendees was about 200.
Year(s) Of Engagement Activity 2018