Research On Aerodynamic Characteristics Of Minibus And Van Mixed Running

With the increase of car ownership, the traffic density is increasing rapidly in our country. Different vehicles should to make up a fixed motorcade in motion because of the needs of the transport task or make up a temporary motorcade by following each other because of some accidental factors. The aerodynamic characteristics of the vehicle can be changed because of mutual interference of flow field between vehicles. In addition, the vehicles before and after in the motorcade is difficult to align in the real situation and this transverse shift can have an effect on the vehicle’s aerodynamic characteristics. The faster the motorcade moves, the effect of the vehicle’s aerodynamic characteristics is more obvious. The aerodynamic characteristics is more complicated in the mixed motorcade consist of large vehicle and miniature vehicle. The miniature vehicle is less mass so it is more easily influenced by the aerodynamic characteristics and the large vehicle has a large volume so it have a large aerodynamic interference to the surrounding environment. The external flow field of the mixed motorcade is more complicated than one car or the motorcade which is consist of Single models of vehicle.This task studied the aerodynamic characteristics of the mixed motorcade which is consist of minibus and van by theoretical analysis, numerical simulation couple with the data of wind tunnel test. Analyzed the causation between the flow phenomenon and the results of mechanical. Conclusions are as follows:First, made the numerical simulation of the single van and minibus used the finite volume method and RNG k-ε two-equation turbulence model by steady numerical method. Then contrasted the numerical simulation and the data of wind tunnel test. Provide a basis for further study to analyze the aerodynamic characteristics of the mixed motorcade.Studied the aerodynamic characteristics of the mixed motorcade which is consist of minibus and van by steady numerical method. The orientation of the vehicle is aligned in the beginning and then change the forward and backward location of the vehicle in the motorcade. Analyzed the affect made by the change of location and we can see that:Compared with single driving,the car in double mixed running team generates air resistance decrease and aerodynamic lift.For the same kind of models, in the latter car position, aerodynamic characteristics have the largest change.But in the same position, the varied range of air resistance in minibus surpasses one in the van, meanwhile the varied range of aerodynamic in the van surpasses one in minibus.Through the steady state simulation, the mixed running team made up of a minibus and two vans in a line is studied. Three working condition was set up by changing the ranking position of three automobiles The effects of change of vehicle position on aerodynamic characteristics of themselves and the team was analyzed in the three working conditions. Compared to single driving, vehicles in three-in-line mixed running team generates air resistance decrease and aerodynamic lift. The aerodynamic characteristics on three car team are more complicated than two car team, which is relative to not only vehicle position but also own and adjacent vehicle models. As for minibus, air resistance is minimum when it between two vans, and the farther forward the position, the greater the aerodynamic lift. But for vans, the more later, the larger windward of forward adjacent vehicles and the smaller the air resistance. After the minibus, first van’s aerodynamic lift is maximum, but first van in the team followed by minibus has least aerodynamic lift. Considering the economy and safety of vehicles in the team, the best formation mode of three-in-line mixed running team is minibus behind two vans. For another, minibus between two vans makes the worst economy, and minibus ahead two vans makes the worst aerodynamic stability and security.The deflective motorcade between minibus and van is studied by means of steady state simulation. The flow field of the interaction is analyzed when the relationship between two vehicles are lateral drift.The model changes, as well as the vehicle flow field. For two minivans, when the distance of lateral deflection is increasing, vehicle aerodynamic resistance increases gradually, pneumatic lateral force changes with a trigonometric function, and the influence of the yawing moment that is behind also benefit from a more volatile. when the distance of the deflective motorcade between minibus and van is increasing, the aerodynamic resistance increases gradually, the fluctuation of the lateral force to minibus is bigger than the van no matter what position the minivan is; The rule of pneumatic lateral force to the vehicle behind changes with a trigonometric function and the fluctuation of the yawing moment is binger than the vehicle ahead.The results of this paper can be used to the motorcade in crosswind environment, hybrid skew convoys of vehicle and overtaking of different kinds of vehicle as the basis and reference.