Many studies relating to vehicle door closure have focused on noise and vibration, and little attention has been given to the pressure rise or velocity distribution inside a cabin. Too high a pressure rise may, however, exert a resistive force when a car door closes and induce a mechanical reaction of the pars flaccida related to passenger comfort. Thus, this study investigates the effects of the angular velocity of the door and the body leakage on variations in the cabin flows. First, tests for the body leakage were performed for 43 vehicles. Then, three-dimensional numerical analyses with a dynamic mesh were performed and experiments were conducted to verify the results. It was found that the pressure rise is a strong function of the door's angular velocity and that the peak pressure increases almost linearly with increasing angular velocity. However, the body leakage has less effect on the pressure rise unless the extent of the leakage is significantly increased. The pressure rise that occurs while closing a cabin door could be greatly reduced by lowering the door's angular velocity or by developing a mechanism that can greatly increase the body leakage temporarily.

Some passenger cars with sunroofs open at tilted positions experience reverse flows into cabin rooms and wind noises much louder than in other cars. In this study, flows around an open tilted sunroof are numerically studied with varying body leakage. The effects of body leakage on ventilation and wind noise of a sunroof are examined, in particular. Furthermore, flow visualization, pressure and wind noise measured from the wind tunnel and road tests are presented. The results show that too small a body leakage results in poor ventilation performance and generates high wind noises around a sunroof. It is therefore very important to secure an adequate body leakage from the early design stage to achieve better performance of a sunroof as well as passengers' thermal comfort.