Tagged Questions
4
votes
3answers
76 views
What about negative Pressure?
Here is something I see :
Let's say the ideal fluid(water here) of density $\rho$ is drawn from a source by a motor and thrown upwards with a velocity $v$. Now we take the power of motor be ...
7
votes
1answer
503 views
Why doesn't a bus blow due to internal pressure?
When one travels in a bus, if he's sitting at any window, he will feel that the air is coming inside. If someone is standing at the open door of the bus, he'll also feel that the air is coming ...
4
votes
1answer
46 views
What is the minimum pressure difference for your ears to pop?
I'm assuming the answer to this largely varies from person to person. Assuming you could instantly change the pressure around your head by amount $\Delta p$, what is the minimum $\Delta p$ for your ...
1
vote
1answer
41 views
Distribution of pressure inside a capsule
How would pressure of an ideal gas be distributed over the inside of a capsule (a cylinder with semi-spheres on the ends)? What about the strain on the material? Is there a general formula for how ...
1
vote
2answers
36 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 ...
6
votes
2answers
138 views
Hydrostatic pressure on a teapot spout
The phenomenon where water flows on the outside side of a teapot spout is named "The teapot effect", and occurs due to a difference in pressure between water and the atmosphere. Consider the image of ...
2
votes
1answer
106 views
Drinking juice through a straw
Why we are able to suck more drink through a larger diameter straw than a smaller diameter straw if $p_1 v_1 = p_2 v_2 = Q$ as per Bernoulli's Principle. The pressure difference I create in mouth ...
4
votes
2answers
125 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 ...
6
votes
2answers
148 views
Why water in the sink follow a curved path?
When you fill the sink with water and then allow the water to be drained, the water forms a vortex.. And then it starts to follow a curved path downwards by effects of gravity..
Why this phenomena ...
0
votes
0answers
142 views
pressure loss in a syringe
I'm currently working on a problem which is really giving me some issues.
The problem concerns the force required to expel water from a syringe. We have a 20ml syringe (which is $2\times10^{-5}$ ...
3
votes
2answers
109 views
Pumping water from a closed column. Will the column get empty or just circualte?
As a picture is worth a thousand words, here is my problem:
It is a closed water column with a bit of air in the top section.
If I run the pump and make the water flow from IN to OUT,
Will the ...
-1
votes
2answers
149 views
A simple logical problem regarding pressure and force
Suppose a 2 meter long pipe, with area of cross section is $1 m^2$. The pipe is vertically placed, with the bottom end closed. Inside the pipe, at the closed bottom end, there is $1 m^3$ of air, ...
0
votes
1answer
159 views
thought experiment involving water pressure
If I were to move the syringe up, and cause it to be stationary, how does that effect the pressure at the bottom of the pipe? How does the movement of this water effect the system setup and ...
4
votes
3answers
185 views
How can I keep a smaller water reservoir's water level at half available when being fed from a larger reservoir? [closed]
I'm trying to create my own ultrasonic humidifier. I ordered the misting part which works great but it only functions correctly in shallow water. So I'd like to feed from a large water reservoir to a ...
6
votes
2answers
189 views
At what velocity does sea water leave a pipe run into a fresh water lake (for equal surface levels)?
If I took a fresh water lake* whose surface is exactly as sea level, and connect it to the sea with a pipe filled with sea water, with both ends of the pipe at exactly the same depth from the surface, ...
4
votes
3answers
129 views
Effect variable cylinder radius has on airflow
Can someone shed some light on the following problem? I'm unable to get any traction on it as I know nothing about fluid dynamics (I'm a computer engineer).
It's a problem I made up over a lunch ...
1
vote
1answer
219 views
Pump pressure required to fill water tower
I have a water pump at a distance of x meters from a water tower located h meters above the pump through a pipe with diameter d. I am not concerned with the exact value just want to make sure my pump ...
0
votes
0answers
138 views
What is the pressure in a vertical pipe that has moving fluid through it?
I have a system like this
When the valve is closed, pressure along any point along the thin tube may be found thru pgh. 1. What about when the valve is opened? 2. Does the top of the jar need to be ...
2
votes
2answers
228 views
Will the siphoning effect help a system pump water upwards if the water's entry and exit points are at the same height?
I am looking to pump water from a pool up to a roof for solar heating (black plastic tubing) and then back into the pool with the original source water. Does the gravitational force of the water ...
5
votes
1answer
318 views
Why is pressure in a liquid the same in all directions?
I'd like answers both in the more intuitive side an on the more precise side.
Thinking of water as "cubes" of water, for example, would allow pressure in the z axis to be independent of the y or x ...
1
vote
1answer
119 views
How would this rapid depressurization of water really behave?
An in-development game(Starbound) recently released a demo of their water physics. At about 39 seconds into the video, a volume of water in a container is released when the cap on the container is ...
1
vote
2answers
158 views
How is energy transferred from one incompressible fluid to another?
When you apply pressure to an incompressible fluid the pressure is transferred. If you stop applying the pressure there is no motion. Volume and density are integral parts of calculating how much ...
0
votes
1answer
115 views
How is external pressure transmitted when a fluid is not enclosed?
Pascal's principle states that pressure applied to an enclosed fluid is transmitted undiminished to every part of the fluid.
How is the pressure transmitted in the case where the fluid is not ...
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 ...
-2
votes
2answers
157 views
Why does the higher pressure of air underneath an aeroplane wing keep it flying?
With aeroplane flight, the wings are shaped so that the air that goes over the top of the wing has to travel faster than the air that goes below the wing. This means that the air below the wing has ...
0
votes
0answers
284 views
Hydraulic System in a Simulation
A simulation project we are on, we have a machine with hydraulics that are powered (They don't just look like they move something, they are the only thing moving/turning/lifting something) - However, ...
1
vote
3answers
943 views
How does the Dyson air multiplier fan create negative pressure?
I'm curious as to how the Dyson air multiplier fan works. So far I understand that it creates negative air pressure that causes air behind and around the device to be sucked into the air stream and ...
0
votes
1answer
2k views
To calculate pressure at point in a vertical water pipe of given diameter
Is it possible to calculate pressure at a point in a pipe, where a solenoid valve shall be placed, given that
the pipe carries water (utility supplied, regular water)
from an overhead tank (at a ...
3
votes
3answers
715 views
Define Pressure at A point. Why is it a Scalar?
I have a final exam tomorrow for fluid mechanics and I was just looking over the practice exam questions. They do not provide solutions. But pretty much I have to define pressure at a point and also ...
3
votes
1answer
492 views
Water under high pressure
If you were to sink a container to the bottom of a deep ocean and seal it there, then bring it up to the surface, would it retain its pressure?
The answer for a gas is obviously yes, but what about ...
5
votes
1answer
1k views
Why do some carbonated drinks fizz more than others?
Wired magazine ran an article this month on carbonation in soft drinks.
If all soft drinks are manufactured effectively identically, why do some types fizz more than others?
For example, root beer ...
11
votes
2answers
436 views
How to model/simulate pressures and flows in a network of pipes
I'm having a hard time finding information on how to model/simulate this. I attached a couple files, both of which show an example tank & pump network. It's just nonsense that I made up for this ...
8
votes
4answers
1k views
Water pressure in free fall
The increasing water pressure as you go deeper is generally explained in terms of the weight of the water column above the observation point pressing down. The question, then, is what would happen if ...
36
votes
11answers
4k views
How long a straw could Superman use?
To suck water through a straw, you create a partial vacuum in your lungs. Water rises through the straw until the pressure in the straw at the water level equals atmospheric pressure. This ...
10
votes
4answers
955 views
How does a steady wind flow generate sound?
When a wind blow through sharp edge, say, edge of a paper, you can see the vibration of the paper and hear the sound.
For this type of oscillation, it should be a damped oscillation with external ...
6
votes
3answers
2k views
Why does the water level equalize in a series of tubes?
Say I have a series of tubes (not the internet) looking like this, where w represents water:
...
