This product is a teaching experimental device used for flow field demonstration. According to the Reynolds number similarity criterion, many flow processes that occur in air can also be demonstrated through experiments in water. The main body of this experimental device is a small precision water tank, which can not only be used to demonstrate the laminar and turbulent processes of the supporting model in the water channel, but also to customize other irregular resistance bodies for users to demonstrate the laminar, turbulent, and swirling processes of these resistance bodies in the flow field.