Drag coefficient for plate perpendicular to airflow

Click For Summary

Discussion Overview

The discussion revolves around determining the drag coefficient for a flat plate that is oriented perpendicular to the airflow, specifically for a plate with a different width-to-height ratio than those typically referenced. The scope includes theoretical considerations and practical applications related to fluid dynamics.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • One participant references a Wikipedia article stating the drag coefficient for a flat plate perpendicular to flow is between 1.98 and 2.05, but questions how to apply this to a plate with a specific b/h ratio.
  • Another participant inquires about the flow conditions, asking whether the flow is laminar or turbulent and requesting the Reynolds number for further assistance.
  • A different participant suggests that the Reynolds number may not significantly affect the drag coefficient for a plate perpendicular to the flow and recommends finding reference measurements for similar conditions.
  • One participant reiterates the importance of flow conditions but later acknowledges a misunderstanding regarding the orientation of the flow, indicating a need for clarity in the original question.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of the Reynolds number and flow conditions, indicating that there is no consensus on how these factors influence the drag coefficient for the specific scenario presented.

Contextual Notes

There are unresolved assumptions regarding the flow characteristics and the specific conditions under which the drag coefficient is being evaluated. The discussion also highlights the potential complexity of vortex shedding and its impact on drag, which remains unquantified.

cxcxcx0505
Messages
26
Reaction score
0
http://en.wikipedia.org/wiki/Drag_coefficient
from wikipedia, it is written 1.98-2.05 for flat plate perpendicular to flow(2D) , but I have a differrent b/h ratio plate, where h=157mm and b=816mm , b/h=5.197

how to get the drag coefficient in this case?

Thanks.
 
Engineering news on Phys.org
What are your flow conditions?

Laminar? Turbulent?

Are we just talking about ambient air? or God blowing on the plate... =)

Give me the Reynolds number and I can help you out.

Cheers =)
 
For a plate perpendicular to the flow the reynolds number will not matter much. That wikipedia page gave a Cd for a 3d flat plate and you will probably be ok using that. Otherwise there is not an easy way to figure this out, your best bet would be to find some reference with similar measurements
 
harrisiqbal said:
What are your flow conditions?

Laminar? Turbulent?

Are we just talking about ambient air? or God blowing on the plate... =)

Give me the Reynolds number and I can help you out.

Cheers =)

Given that this is going to be entirely pressure drag, the state of the flow (laminar vs. turbulent) won't matter a bit. The only thing that could potentially play a role in would be the nature of the vortices that would be shed behind the plate, but the aft side is going to be massively separated and emitting vortex streets regardless.
 
Apologies,

Did not properly read OPs question. I thought he was talking about parallel flow on plate.

Whoops =)
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 3 ·
Replies
3
Views
9K
  • · Replies 40 ·
2
Replies
40
Views
5K
  • · Replies 5 ·
Replies
5
Views
29K
  • · Replies 26 ·
Replies
26
Views
14K
  • · Replies 1 ·
Replies
1
Views
5K
  • · Replies 4 ·
Replies
4
Views
18K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 6 ·
Replies
6
Views
6K