Tagged Questions
4
votes
1answer
66 views
Existence and uniqueness of Stokes flow
What are the solution existence and uniqueness conditions for Stokes' flow?
$$\nabla p = \mu \Delta \vec{u} + \vec{f}$$
$$\nabla \vec{u} = 0$$
Maybe you could also provide some articles or books ...
1
vote
2answers
32 views
Water draining from a height into the bottom of a reservoir
If I hang one 5 gal. Bucket directly above another, put a hole in the bottom of the upper bucket with a tube inserted just inside hanging all the way to the bottom of the lower bucket and fill the ...
1
vote
1answer
42 views
Computational Fluid Dynamics methods
I have read some articles about the finite difference method on a cartesian orthogonal grid. I understand how it works when Dirichlet boundary conditions are used, or when Neumann boundary conditions ...
2
votes
1answer
20 views
Application of plasma actuators for flow control of moving objects
I've recently been to a converence on plasma physics were, to my surprise, a lot of presentations were concerned with plasma actuator.
Could someone, preferably in the field, tell me how long people ...
4
votes
2answers
57 views
When is a flow vortex free?
To solve problems in fluid dynamics one states often the assumption that the flow is vortex free i.e.
$rot(u) = 0$
It is a basic assumption which is needed for potential flow problems etc.. My ...
4
votes
2answers
122 views
Physics behind the flow of gas coming out of a balloon
I'm working with stratospheric balloons (latex ones) and I want to put a valve on it so it can float for a longer time. I'm trying to define which valve I should use, which demands I estimate the flow ...
1
vote
1answer
126 views
how to determine if a vortex is laminar or turbulent
In a cylindrical chamber with a high diameter-to-height ratio; a fluid is tangentially injected. there is an axial exit to the cylinder.
how do I determine if the vortex so formed is laminar or ...
5
votes
1answer
141 views
Why do air bubbles stick to the side of plastic tubing?
I'm watching water with air bubbles flow through transparent plastic tubing. The inner diameter is a few mm. Bubbles typically are the same diameter as the tubing, with length about the same or up ...
1
vote
2answers
63 views
How would I work this continuity problem?
I am trying to design a system for a project and I need some input on if this is right or not.
I have $10 \frac{kg}{s}$ of fluid flowing through a pipe. It breaks up into $10$ 1 inch diameter pipes. ...
0
votes
1answer
130 views
What is the particle residence time for given flow rates of gas mixture components?
For two different chemical substances there are two open valves with flow rates $$Q_1=a\frac{m^3}{h}\ \text{ and }\ \ Q_2=b\frac{m^3}{h},$$ leading into seperate cables.
Next, the cables join, the ...
0
votes
0answers
129 views
Reduction in velocity in pipe
I have two pipes divided from main pipe. If I add one more pipe, what would be the amount of velocity in each pipes. I know the velocity of main pipe, then diameter and radius of each pipe.
Edit:
1) ...
7
votes
5answers
314 views
Zigzag flow of water along a vertical glass window
I've observed this behavior many times. When it rains, the rainwater will form vertical channels along a glass window. The flow of water is mostly confined within these vertical channels and the ...
4
votes
2answers
2k views
Flow of liquid among branches
If water is flowing through big pipe is branched into 4 branches of small pipe. Lets say the flow is around 4 m/sec.
I have the following questions:
What will be the flow rate in each of the ...
2
votes
1answer
410 views
How much water must flow trough canal to maintain a constant water deep?
In order to maintain a constant water deep in canal, how much water must flow trought the pipe ?
As shown on picture, canal have a rectangular shape.
I don't know if canal length have an influence.
...
2
votes
2answers
279 views
Vortex street and Reynolds number
Its been stated in Wikipedia regarding Reynolds number(Re) that "laminar flow occurs when Re<2300 and turbulent flow occurs when Re>4000. In another wiki file related to Kármán vortex street it has ...
1
vote
3answers
8k views
Relation between water flow and pressure
Is there any equation that states the relation between pressure and water flow.
I.e. Let's say that in 1 hour with 8mca (water collum meters) pressure I obtain 50m3. What if (giving the same ...
3
votes
3answers
142 views
Analogies between physics and packet-switched networks
Suppose two entities in a communication networks (sender and receiver) are connected with a tube so that water can be pumped from the sender to the receiver. If we also assume that between sender and ...
1
vote
1answer
280 views
What is the pressure drop in a venturi with a compressible fluid?
I would like to know if there is an equation to predict the pressure drop in a venturi device using a compressible fluid as the working medium. In particular, I'd like to use this equation to predict ...
2
votes
1answer
241 views
Calculating spacecraft water leak flow rate
A large container of heated water is floating in space. How can I calculate leak rate if a small puncture is opened?
I'm assuming the water is kept at 298K and in the liquid state inside the chamber.
...
1
vote
0answers
64 views
Discharge of a propeller in a yield-stress liquid
What form does the discharge stream of a propeller take in a Herschel-Bulkley fluid, chracterised by having a certain yield stress, shear between layers only occurs beyond that stress.
This situation ...
2
votes
3answers
776 views
What is the velocity area method for estimating the flow of water?
Can anyone explain to me what the Velocity Area method for measuring river or water flow is?
My guess is that the product of the cross sectional area and the velocity of water flowing in a pipe is ...
2
votes
1answer
498 views
What is the shear stress of a fluid?
One book defines the shear stress $\tau$ of a (Newtonian) fluid as
$$\tau = \eta \frac{\partial v}{\partial r} $$
where $\eta$ is the viscosity. There is not much context, so I've made some guesses. ...
2
votes
2answers
199 views
Is there other uses of flow-straighteners than flow-metering?
Flow-straighteners are used before flow-meters because they remove disturbances from the flow and achieve nearly-fully developped velocity profiles. But is there any other uses of flow straighteners ...
2
votes
1answer
252 views
Air flow coming out of a fan feels much stronger than air flow coming in. Why? [duplicate]
Possible Duplicate:
Why is exhaling more forceful than inhaling?
If I put my hand behind my computer's system block, I can feel a very strong flux of air coming out, as it is being pushed ...
