| 摘要 |
A front crossbar (12) of a roof rack provided above a roof (11) along the width of a vehicle comprises an upper surface (18) and a lower surface (20). The upper surface ()18) is smoothly curved and convex toward the upper direction, and the upper surface (18) introduces an attached flow of air from the front of the vehicle to the rear of the vehicle. The lower surface (20) of the front crossbar (12) comprises a flow compression face in the front of the lower surface (20), a flow leading face in the center of the lower surface, and a flow separation portion in the rear of the lower surface. The flow compression face is hollowed toward the center point of the cross-section of the front crossbar (12), and introduces and compresses the air flow from the front of the vehicle. The flow leading face is a smooth convex arc of a circle as the cross-section, and leads the air flow compressed from the front of the front crossbar (12) to the rear of the front crossbar (12). The flow separation portion is notch shaped like a step, and separates the air flow from the front of the front crossbar (12). Since the difference of the pressure, the velocity, or etc. between the two air flows separated to the lower and upper sides of the front crossbar (12) is high, a Karman vortex which causes wind noise of the front crossbar (12) can be avoided. Consequently, the wind noise of the roof rack can be reduced efficiently. <IMAGE> |
