Abstract: In an undercover structure according to the present invention, a first cover part that is a lowermost part of an undercover has a first rear end positioned ahead of a front wheel axle. Further, a curved part with a predetermined curvature is formed at the first rear end of the first cover part in a side view. This generates a strong negative pressure in a region ahead of the front wheel axle 21. Accordingly, the flow rate of air flowing to each wheelhouse 23 decreases (the flow rate of the airflow between a road and a vehicle generated along the bottom surface of the first cover part 15a of the undercover 15 increases). This causes an attraction force that attracts the vehicle to a road surface to act on a vehicle body of the vehicle, thereby making traveling stability more excellent.

Abstract: There is provided a wheel device for a vehicle including: a wheel having an opening formed between adjacent spokes; a brake mechanism located inside the wheel in a vehicle width direction and having a brake caliper and a brake rotor; and an arc portion extending in a circular direction in the opening and suspended between the adjacent spokes. The arc portion has a recessed portion recessed outward in the vehicle width direction inside thereof in the vehicle width direction, and the arc portion and the brake caliper are located at such positions that they overlap with each other in a state viewed in the vehicle width direction.

Abstract: A moving body that moves at least one of in water or along a water surface, in accordance with a person moving on the water by stepping with feet in an alternating manner, includes a movement information acquiring unit that acquires information concerning movement of a foot of the person or a worn item worn on the foot of the person, and a control unit that, when the foot of the person moves away from the moving body, causes the moving body to move to a stepping destination of the foot based on the information acquired by the movement information acquiring unit. A moving body system includes the moving body and the worn item.

Abstract: Tracer particles together with air are jetted from a nozzle of a seeder into a hood, the air is guided by a collision surface of the hood, deflected to a downstream side in an airflow direction in a wind tunnel, and flows out into the wind tunnel through an opening of the hood. Tracer particles having a large diameter fly straightly without being drifted by the deflected air and collide with the collision surface and are trapped thereon and are prevented from being supplied into the wind tunnel. Tracer particles having a small diameter are drifted by the deflected air, thereby deflected, and supplied into the wind tunnel without collision with and adhesion to the collision surface.

Abstract: An aerodynamic noise reduction device reduces aerodynamic noise originating from a separation region located downstream of a step portion protruding from a surface of an object placed in an airflow. Since the step portion protrudes from the surface of the object placed in the airflow, aerodynamic noise is generated from the airflow separation region located downstream of the step portion. However, by forming an air discharge vent at the step portion at a position near a point, in the separation region, where a Reynolds stress is at its maximum and by discharging air from the air discharge vent toward the point where the Reynolds stress is at its maximum, the velocity gradient in the separated shear layer in the separation region is mitigated to decrease the maximum value of the Reynolds stress. The aerodynamic noise is thus effectively reduced.

Abstract: Tracer particles together with air are jetted from a nozzle of a seeder into a hood, the air is guided by a collision surface of the hood, deflected to a downstream side in an airflow direction in a wind tunnel, and flows out into the wind tunnel through an opening of the hood. Tracer particles having a large diameter fly straightly without being drifted by the deflected air and collide with the collision surface and are trapped thereon and are prevented from being supplied into the wind tunnel. Tracer particles having a small diameter are drifted by the deflected air, thereby deflected, and supplied into the wind tunnel without collision with and adhesion to the collision surface.