凸状涡形轮

例句：

1. 1. The car's engine is made up of many small, concave, and convex parts.
   汽车的发动机由许多小的、凹的和凸的部分组成。
2. 2.The gearbox has a complex design with multiple convex and concave surfaces.
   齿轮箱设计复杂，具有多个凸面和凹面。
3. 3. The shape of the wheel is designed to provide a smoother ride and reduce friction.
   车轮的形状被设计成提供更平滑的骑行体验并减少摩擦。