Calculating the Force of Moving Water: Vehicle Hydrodynamic Drag Equation

In summary, the conversation discusses the possibility of using an equation to calculate the force of moving water and aerodynamic drag. The parameters for such an equation would include water depth, water speed, water density, and surface area of the vehicle. The equation for hydrodynamic drag is F=Apv^2, while the equation for aerodynamic drag is F=0.5PV^2CdF, where P is density, V is velocity, Cd is coefficient of drag, and F is frontal area. The coefficient of drag would vary depending on the part of the vehicle exposed to the water or air.
  • #1
Ideologue
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Does anyone know of an equation I may use to calculate the force of moving water? I am trying to theoretically workout the resistive force a vehicle would meet if it were to drive upstream (hydrodynamic drag).

I am assuming the main parameters such an equation would include are water depth, water speed, water density and the surface area of the exposed parts of the vehicle such as the portion of its tyres submerged in the stream.

Thanks.
 
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  • #2
Force=v*rate of change of mass
F=Apv^2, where p = density of water, v=velocity of water, A=surface area
 
  • #3
Thank you very much, Harmony.
 
  • #4
I am wondering now if it is possible to use exactly the same equation for calculating aerodynamic drag as is used for calculating hydrodynamic drag?

Instead of using a figure for air density, a figure for water density is employed. The coefficient of drag remains the same.

What do you think?

Aerodynamic drag is: F = 0.5PV²Cdf

Where:

P = air density
V = velocity
Cd = coefficient of drag
f = frontal areaEdit: Of course the coefficient of drag would be specific to the part of the vehicle subjected to the flowing water.
 

FAQ: Calculating the Force of Moving Water: Vehicle Hydrodynamic Drag Equation

What is the vehicle hydrodynamic drag equation?

The vehicle hydrodynamic drag equation is a mathematical formula used to calculate the force of moving water on a vehicle. It takes into account factors such as the velocity of the water, the shape and size of the vehicle, and the density of the water.

Why is it important to calculate the force of moving water on a vehicle?

Calculating the force of moving water on a vehicle is important for understanding the potential impact of water on the vehicle's movement. This information can be used to make design decisions for vehicles that operate in or on water, such as boats, submarines, or underwater vehicles.

What are the variables in the vehicle hydrodynamic drag equation?

The variables in the vehicle hydrodynamic drag equation include the velocity of the water, the cross-sectional area of the vehicle, the drag coefficient, and the density of the water. These variables are used to calculate the force of water on the vehicle.

How can the vehicle hydrodynamic drag equation be applied in real-world situations?

The vehicle hydrodynamic drag equation can be applied in various real-world situations, such as designing boats or submarines, predicting the drag force on a vehicle in a river or ocean, or evaluating the performance of underwater vehicles.

Are there any limitations to using the vehicle hydrodynamic drag equation?

Yes, there are limitations to using the vehicle hydrodynamic drag equation. It assumes that the water is moving in a straight line and does not take into account factors such as turbulence or waves. It also does not consider the effects of other forces on the vehicle, such as wind or currents.

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