Viscosity:Viscosity is a measure of a fluid's resistance to flow. It determines how easily or difficultly a fluid can deform or move. For example, honey has higher viscosity than water.
Reynolds Number: The Reynolds number is used to predict whether the flow of a fluid will be laminar or turbulent. It depends on factors such as velocity, density, viscosity, and characteristic length.
Drag Force: Drag force is the resistance experienced by an object moving through a fluid. In turbulent flow, drag force increases due to the chaotic motion of the fluid particles around the object.