Characteristic lengh in Reynolds number

In summary, the characteristic length in Reynolds number is a length scale that is used to determine the type of flow, whether it is laminar or turbulent. It is important in Reynolds number calculations and is calculated by measuring the length of the object or flow field in the direction of the flow. In fluid dynamics, it is significant as it affects various properties of the flow and can be changed depending on the geometry of the object or flow field.
  • #1
mastermechanic
108
15
As we know $$Re= \frac{ρ.v.l}{μ}$$ The characteristic length (l) is said to be representative of the problem but according to what should we choose this length? I mean if we want to calculate Reynolds number of a wing of plane, should we choose the length or the width?
 
Engineering news on Phys.org
  • #2
Which do you think and why? In fact, there isn't really a correct answer here. You just have to choose based on the physics you hope to study. Really there are many possible versions of ##Re## even just on a wing depending on the phenomenon of interest.
 
  • Like
Likes Chestermiller

1. What is the characteristic length in Reynolds number?

The characteristic length in Reynolds number is a length scale that is used to determine the type of flow, whether it is laminar or turbulent. It is typically the length of the object or flow field in the direction of the flow.

2. Why is characteristic length important in Reynolds number?

The characteristic length is important in Reynolds number because it is used to calculate the Reynolds number, which is a dimensionless number that indicates the type of flow. It helps to determine the dominant forces and the behavior of the fluid flow.

3. How is characteristic length calculated?

The characteristic length is calculated by measuring the length of the object or flow field in the direction of the flow. For example, for a cylinder, the characteristic length would be its diameter. For a pipe, it would be the length of the pipe.

4. What is the significance of characteristic length in fluid dynamics?

In fluid dynamics, the characteristic length is significant because it is used to determine the type of flow, which can affect the drag force, pressure drop, and other properties of the flow. It also helps to compare different flows and understand their behavior.

5. Can characteristic length be changed?

Yes, the characteristic length can be changed depending on the geometry of the object or the flow field. For example, the characteristic length for a pipe can be changed by altering its diameter. In some cases, the characteristic length may not be well-defined, and an average length may be used instead.

Similar threads

Nozzle loss coefficient that increases with Reynolds number?
    • Mechanical Engineering
Replies
3
Views
1K
Critical Reynolds number and characteristic length
    • Mechanical Engineering
Replies
10
Views
2K
How can I calculate the Reynolds number if the particle velocity is unknown?
    • Mechanical Engineering
Replies
14
Views
4K
Hydrodynamic forces on a foil, Reynolds number, viscosity
    • Mechanical Engineering
Replies
17
Views
3K
Understanding the Importance of Particle Reynolds Number in Fluid Dynamics
    • Mechanical Engineering
Replies
6
Views
14K
I How is the Reynolds number derived (is my derivation wrong)?
    • Other Physics Topics
Replies
6
Views
2K
Matching Reynolds Number in Scale Model Wind Tunnel Testing
    • Mechanical Engineering
Replies
1
Views
3K
Can Reynolds Number < 70 Cause Turbulence in Elbow Fittings?
    • Mechanical Engineering
Replies
20
Views
4K
I Laminar-turbulent transition and Reynolds number
    • Classical Physics
Replies
5
Views
941
Predicting flow rates of a pressure driven system
    • Mechanical Engineering
Replies
8
Views
1K

Hot Threads

Recent Insights

Back
Top