<p>You are looking for the drag force imposed by the fluid flow on an object:</p>

<p>$$F = \dfrac{1}{2} \rho v^{2} C_D A$$</p>

<p>where $\rho$ is the density of the fluid, $v$ is the speed of the flow, $C_D$ is the <a href="http://en.wikipedia.org/wiki/Drag_coefficient">drag coefficient</a> depending on the shape of the object, and $A$ is the surface area normal to the fluid flow.</p>

<p>Let's plug in some characteristic numbers for scaling. For a current of 1 m s$^{-1}$, fluid density of 1000 kg m$^{-3}$, drag coefficient of 1, surface area of 1 m$^2$, the force imposed by the fluid on the object, according to the equation above, would be 500 N.</p>

<p>Note that this equation is valid only for high $Re$ flows that produce turbulence in the wake of the object. The drag coefficient is estimated empirically and takes into account both skin and form drag of the object.</p>

CC BY-SA 3.0
2014-04-24T21:47:48.730Z
2014-04-24T21:47:48.730Z
milancurcic
<p>I would like to calculate the force of an underwater current on a meter by meter plate (or any other unit that you may use to represent it) that is standing in front of the current.
How do I calculate it? What parameters do I need?</p>

<models><ocean-currents><numerical-modelling>
What is the force imposed by underwater currents?
Someonation
# What is the force imposed by underwater currents?

(Asked by: username_0 on 2014-04-24)

I would like to calculate the force of an underwater current on a meter by meter plate (or any other unit that you may use to represent it) that is standing in front of the current.
How do I calculate it? What parameters do I need?

**Tags:** models, ocean-currents, numerical-modelling


---

## 1 answers

### Answer by username_1 on 2014-04-24. Score: 13 | Accepted answer

You are looking for the drag force imposed by the fluid flow on an object:

$$F = \dfrac{1}{2} \rho v^{2} C\_D A$$

where $\rho$ is the density of the fluid, $v$ is the speed of the flow, $C\_D$ is the [drag coefficient](http://en.wikipedia.org/wiki/Drag_coefficient) depending on the shape of the object, and $A$ is the surface area normal to the fluid flow.

Let's plug in some characteristic numbers for scaling. For a current of 1 m s$^{-1}$, fluid density of 1000 kg m$^{-3}$, drag coefficient of 1, surface area of 1 m$^2$, the force imposed by the fluid on the object, according to the equation above, would be 500 N.

Note that this equation is valid only for high $Re$ flows that produce turbulence in the wake of the object. The drag coefficient is estimated empirically and takes into account both skin and form drag of the object.


---

