A LES Study on the Effect of Periodic Gusts on a Truck Model

Paper in proceeding, 2017

This work presents an application of the Large Eddy Simulation Coherent Structures Model (LES-CSM) equations for an external vehicle flow. In particular, the flow around a generic truck is simulated. The model is forced to oscillate in order to represents a more realistic ground vehicle flow condition, where gusts (of different natures) define the unsteadiness of the incoming flow. In this numerical study, the Reynolds number is Re = 4 × 10 4 based on the width of the model W = 0.152 and the incoming velocity U inf = 4.26m/s. The model is forced to oscillate with a yaw angle 10 ◦ > β > −10 ◦ and a non-dimensional frequency St = f W/U inf = 0.06. The effect of the periodic motion of the model is compared with the quasi-static flow condition. Overall, the effect of oscillation changes drastically the flow, arising an hysteresis behaviour and complete different features, when compared to the static configuration. This study is relevant to better understand real flow conditions, with the ultimate goal to implement an effective active flow control strategy for aerodynamic drag reduction.