Working area for drag reduction agents (dra) is in turbulence area, and it can reduce resistance as well as increase transportation effectively.
减阻剂的作用区域在流体的湍流区，它能有效的降低流体阻力增加流量。
2
Entry - as your hand enters the water to full extension you want to have minimum resistance and turbulence.
入水-当手掌入水时，你要想阻力和湍流最小，手掌就要完全伸直。
3
The resistance created by her physical features and a sudden change in direction can be seen by the bubbles and drag turbulence that follows her. This is not a good follow-through.