What is the solution to the circular duct problem?

AI Thread Summary
The discussion focuses on solving a problem related to a circular duct with a specific diameter, air velocity, density, and viscosity. Participants are tasked with calculating the mean outlet velocity through a circumferential slot, determining the gauge pressure in the duct, and analyzing the resultant force on a cup. Key considerations include the comparison of airflow entering and exiting the duct, as well as the implications of air's compressibility. The conversation highlights the need for clarity on how to apply fluid dynamics principles and relevant equations to find the solutions. Understanding these factors is crucial for accurately addressing the circular duct problem.
Joon
Messages
85
Reaction score
2

Homework Statement


Shown in the figure attached.
Circular duct with a diameter of 150 mm, strikes a cup and exits through a circumferential slot to the atmosphere.
Mean velocity in the duct = 100 ms^-1
Air density = 1.1 kg/m^3
Dynamic viscosity of air = 19.05 x 10^-6 kgm^-1s^-1

(a) Determine the mean outlet velocity, knowing the slot has an area of 6597 mm^2
(b) Determine the gauge pressure in the duct (point A), knowing that A and B are in the same horizontal plane
(c) Draw an appropriate control volume and hence determine the resultant force acting on the cup

Homework Equations

The Attempt at a Solution


I don't know where to start. How do you use air density and viscosity?
 

Attachments

  • 38391396_2100219723575365_4675978393198526464_n.jpg
    38391396_2100219723575365_4675978393198526464_n.jpg
    25.8 KB · Views: 415
Physics news on Phys.org
Joon said:
(a) Determine the mean outlet velocity, knowing the slot has an area of 6597 mm^2
Well, I can help with the first part. Someone else will have to jump in for the rest.

How much air is entering the duct each second?
How much air is leaving the slot each second?
Are they the same or different? Why?
How do the areas of the duct and the slot compare?
 
Tom.G said:
Well, I can help with the first part. Someone else will have to jump in for the rest.

How much air is entering the duct each second?
How much air is leaving the slot each second?
Are they the same or different? Why?
How do the areas of the duct and the slot compare?
Air is compressible.
 
Is it air flowing through the duct, or some other fluid?
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Calculating Fluid Velocity in a Circular Duct
Replies
2
Views
2K
What is the Average Flow Rate in a Room with Circular Ducts?
Replies
3
Views
5K
Power required to rotate a disc in a fluid
Replies
2
Views
2K
How Do You Calculate Airflow and Pressure Changes in a Duct System?
Replies
3
Views
2K
At what distance does a seaplane's boundary layer transition to turbulence?
Replies
1
Views
2K
What Is the Reynolds Number for Fluid Flow in a Tube?
Replies
1
Views
1K
Problem about Hagen-Poiseuille law and pump
Replies
15
Views
5K
Power of Sound Wave at distance
Replies
2
Views
2K
Two Balls Drop, what happens to the distance?
Replies
9
Views
9K
Fluid Mechanics- inviscid fluid pressure in a pipe
Replies
11
Views
2K

Hot Threads

Recent Insights

Back
Top