Experimental investigation has been performed to study the film cooling performance of the cylindrical holes embedded in sine-wave shaped trench. The sine-wave shaped trench is got by changing the trailing edge of the transverse trench into sine-wave shape; the holes are located next to the peaks of the wave. The sine-wave shaped trench hole is expected to get a wider spread of the cooling jet in the span-wise direction. The film cooling effectiveness and discharge coefficient of the sine-wave shaped trench hole configurations with different trench depths (0.75D, 1D) and wave peaks (1D, 2D) have been measured using the transient thermal liquid measurement technique. The blowing ratio covers a range from 0.5 to 2.0. The transverse trench hole was also investigated as a basis of comparison. Thermal and hydrodynamic fields were investigated numerically using Reynolds Averaged Navier Stokes (RANS) simulations with realizable k-ε turbulence model and enhanced wall treatment. Results show that downstream the sine-wave shaped trench, the film cooling effectiveness is higher in the region between the holes. That’s due to the jet spread wider under the influence of the anti-counter-rotating vortices which caused by the sine-wave shape. With the increasing blowing ratio, the film cooling effectiveness of the sine-wave shaped trench hole increases. The larger trench depth produces higher film cooling effectiveness in the region between the holes. With the increasing wave peak, the film cooling effectiveness is increased in the region between the holes due to that more of the jet flows to the wave valley. The discharge coefficients of the sine-wave shaped trench configurations are higher than the transverse trench which means that the sine-wave shape trench has lower flow resistance.

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Autonomous driving vehicles have some advantages, such as alleviating tasks of drivers and reducing carbon emissions. With the advancement of intelligent network connection technology, autonomous driving vehicles are showing a trend of practicality and popularization, so it is crucial to study the decision-making mechanism of autonomous driving vehicles. This paper focuses on the lane-changing decision-making behavior of autonomous driving vehicles. Firstly, the objective quantification of lanechanging intention is carried out to reasonably show the lane-changing intention of autonomous driving vehicles as a prerequisite for lane-changing decision-making. Besides, the lane-changing collision probability and the lane-changing dynamic risky coefficient are introduced, and explore the dynamic influencing factors of lane-changing process for autonomous driving vehicles. Based on the game theory, the decision-making behavior model of the lane-changing game for autonomous driving vehicles is established. Analyze the decision-making behavior mechanism of lane-changing, so that the autonomous driving vehicle can change lanes safely and reasonably. Finally, with SUMO software, the traditional LC2013 lane-changing model and the decision-making behavior model of the lane-changing game are used for simulation experiments and comparative analysis. The results show that under the decision-making behavior model of the lane-changing game, the average speed of vehicles increases by 3.6%, and the average number of passed vehicles increases by 10.3%, which has higher stability, safety, speed gains, and lane utilization. The modeling of lane-changing game strategy for autonomous driving vehicles comprehensively considers the dynamic factors in the traffic environment, and scientifically shows the lane-changing decision-making mechanism of autonomous driving vehicles.INDEX TERMS Intelligent transportation, autonomous driving, lane-changing behavior, decision-making method, game strategy.