Research on aerodynamic layout of lift wings on a high-speed train under boundary constraint

The aerodynamic lift cooperative high-speed train is an innovative concept by arranging tandem lift wings on the train body, such that it can improve the aerodynamic lift of the train, achieve the overall energy saving of the train operation and reduce the train's life cycle cost. Under the constraint of high-speed rail, the layout of tandem lifting wings is significantly affected by the wall interference and wing-wing interactions. In this study, numerical simulations are conducted to understand these two effects, and an optimal six-wing layout is proposed. The results show that as the wall-normal height of the lift wing increases, the wall effect on the wing gradually weakens. When the wall-normal height is greater than twice the chord length of the wing, the wall effect on the lift wing disappears. The wing spacing and wall-normal height difference of the double-wing layout can have great impacts on the aerodynamic performance of the wings. As the wing spacing and wall-normal height difference increase, the influence of the front wing on the lift coefficient of the rear wing gradually decreases. For the six-wing layout, the largest lift is generated when the wings are located at the same wall-normal height. Under this configuration, the averaged lift coefficient is 1.1184, the averaged drag coefficient is 0.21, and the total lift accounts for 26.66% of the weight of a single train carriage.