# flow

1. ### Fluid Flow help

1. Homework Statement A 15 cm. radius cylindrical air duct is used to replenish the air of a room 10 m.*6 m.* 3m. Every 10 minutes. Determine the speed of the air through the duct in m/s. A1=15 V1=? A2=19 V2=0 2. Homework Equations A1V1=A2V2 3. The Attempt at a Solution 3.14*15^2 * ?=...
2. ### Flow rate of a syringe

I am trying to come up with a mathematical model so that, when the displacement of the plunger of a syringe is know, I can calculate the amount of a specific liquid in the barrel. Or the relationship between the speed of the plunger and flow rate at the tip of the needle (Again assuming that the...
3. ### High school project -- Finding mass flow rate, air velocity

Hi, First-timer here! I'm designing a physics project that involves pumping a certain pressure of air into an empty bottle. SETUP: The bottom of the bottle has a small hole through which a thumb tack fits tightly; the top (cap-side) has a valve through which the air is inserted. The bottle is...
4. ### Determing flow of a closed loop parallel pumping system

Hi all, How would one go about determining the flow(GPM) of a closed loop parallel piping system. I believe this has to do with the pressure intake and outlet of the pump as I have a pump in the mentioned system rated at 4350GPM@50Hz but it is pumping at 4500 GPM at 37Hz, Thank you all for...
5. ### Force applied by a constant stream of particles

1. Homework Statement I'm making a program that draws a graph of the weight of an hourglass. Obviously at first we know the weight, and as the grains begin to fall it decreases by the amount of mass in free fall. However I ran into a problem when the grains begin to hit the bottom. It's...
6. ### Askew Pitot tube, airplane velocity measurement

1. Homework Statement A horizontal Pitot tube (with one end open for airflow and another closed) is accidentally installed into an airplane askew, so that the tube is not horizontal. Instead the closed tube end is higher (in the y-direction of a xy-plane) than the inlet end. How does this...
7. ### Error Propagation

I tried posting this question in this forum a couple of weeks ago, but didn't get an answer to my question. I'm going to try posting it again using the formatting template so that it is hopefully clearer. I am also not sure if this is the right forum to be posting this in. It is a problem I ran...
8. ### Pressure vs Flow in a pipe

A question was posed to me with the following diagram. http://imgur.com/6ltYKd5 11 Sprinklers, in series with identical heads, but 10 and 11 displaying a much smaller spray pattern. 1. Is this possible, and under what circumstances. 2. What would a good solution be to prevent this? My...
9. ### Nominal Linear Velocity Gas flow

Hello, thanks in advance for your help, I am not a physicist, however have a fairly good grasp on mathematics, also this isn't homework or an assignment but a real world problem. Currently trying to create a system with a nebulising gas at a linear velocity of 350 m/s. The calculations...
10. ### Change in gauge pressure using viscous flow through a pipe.

1. Homework Statement Water flows at 0.25 L/s through a 9.0-m-long garden hose 2.0 cm in diameter that is lying flat on the ground. The temperature of the water is 20 ∘C. What is the gauge pressure of the water where it enters the hose? Side question: does the velocity of the water flow need...
11. ### Can temperature affect the mass of water

Hi there guys, I'm conducting an experiment to calculate the mass flow rate of water. Bellow is a copy of the procedure: 1) Weigh the mass in kg of a container 2) Connect a flow meter to a tap (any source) with a pipe and insure the departure pipe goes into a sink 3) Open the tap an increase...
12. ### Mass Flow of Snow while Plowing?

1. Homework Statement Lets say I am plowing snow in a straight line using a standard V-plow. The angle of the V between both blades is 130 degrees. The coefficient of kinetic friction between the blades and the snow is about .1. The speed of the plow is 5 mph or 2.2 meters per second. The...
13. ### Flowmeter Impact from Changing Pressure

I have an argon piping system. The pressure is set at 50 psi. Assume no pressure drop. I have a flowmeter that is calibrated to run at 25 psi. Basically, I want to know what the "new" scale will be on the flowmeter as a result of the increased pressure (from 25 to 50 psi). In other words...
14. ### 488nm LED's?

Why cant I find any LED's at 488nm? Im trying to find a cheaper light source than the traditional argon ion laser for a possible fluorescence activated cell sorter. See link below for schematic. Does anybody know a good retail site for lights in this spectrum I cant find good results with...
15. ### Flow of Water in a plastic bottle

1. Homework Statement You open the plastic bottle lid to take a drink,and notice fluid flowing from a small hole in the bottom of the bottle. You put the lid back on and the flow stops. Explain why the flow did not start until the lid was off. Explain why the flow stopped when the lid was put...
16. ### Gas confusion -- cooling air in a pipe using venturis and mixing

Hello everyone! I am new here. I have used this forum on and off through google searches in the past and learned a fair bit from the posts. This is the first time asking anything. The question is probably extremely simple but has been overrun in my head for a week! It is in regards to...
17. ### Electricity. What kind of current should I use?

Look, I found that there exist two kind of electric current: conventional flow and electron flow. I have read that in every situation I have to use the conventional flow, however I'm going to work with electric circuits using copper wires. In solids, only negatively charged particles (electrons)...

How to calculate how much flowrate from blower i can push water pool 2,75m*1,8m down by 1,25m in 1 sec? Note : Blower Pressure 0.03 bar - 0.035 bar There is an empty room above the water pool with dimension of 2.75m*1.8m*1.7m This process happen in a closed chamber...
19. ### Simulation error messages solidworks - invalid goals

I am running a simulation on a flat plate heat exchanger and the solver is coming up with some error messages. The first says that a vortex crosses the pressure opening and the second says that my heat transfer rate goals are invalid. How can I get the heat transfer goals to be valid as I need...
20. ### Nozzle problem between subsonic and supersonic speed & nozzle area

Hi all, I have really a confusion between subsonic and supersonic speed evolution when the area decrease or increase I have a problem to understand why in supersonic regime the velocity evolution in a nozzle is adverse of the subsonic regime? for example in subsonic regime, when the area...
21. ### Determine the Rate of Change of Pressure Across a Valve

Hello, I am Primarily a Software Engineer, but have some background knowledge from my A-Level and Uni days. However, I have the following problem. I'd like to find out the rate of change in pressure across a valve. Here are the things I know about the system: Cv at 100% open = 0.004 (I...
22. ### Calculations for Poncelet (undershot) waterwheels

Could anyone provide me with, or point me in the direction of, any calculations for the design of Poncelet water wheels? Number of blades and blade shape/curvature in particular. I've had a trawl through the internet and looked through some papers but can't find much understandable information.
23. ### Water Pressure in an Isolated System

So I'm more into electricity, so fluids is not really a forte at all. But I have been thinking about this, and there must be some fundamental issue in the way that I view fluid pressure. Conditions: 1. I have a metal pipe, incompressible 2. There is water in the pipe, (incompressible? ...
24. ### Water vs. water/glycol flow rates

I'm trying to get a rough idea of how flow rate through a round, sharp edged orifice is affected when a fluid is water/glycol versus pain water. In this circumstance, it's 30% water, 55% Dihydroxydiethyl Glycol and 15% Polyalkylene Glycol. I don't need exact numbers at this point, just a...
25. ### Pressure in Pump Systems

OK, So I have been having an on and off debate with my family about this. I saw a pump at Home Depot that said it has a 30 ft head. Then it went on to show that the flow rate varied as the output of the pump changed in height. Now I thought that this was wrong. I just finished a course in...
26. ### Novice Electrical Guy with a Mechanical Question

Hello All. This is my first post, and I hope it is not too simplistic, but I am out of my normal line of work here. I am trying to understand the relationships between flow, velocity, and cross sectional area with gases and fluids(air and water). Imagine a large vertical, cylindrical tank...
27. ### Volume flow through a one side closed capillary

Hi everyone, I'm doing a simulation and need some help. A capillary which is closed on both ends with the length l (x=0 to x=l), with a radius R and the volume pi*R^2*l is dropped on a parachut at the time t=0 from a hight h above ground. At t=0 the pressure inside the capillary is p_i0 (this...
28. ### Probe/anemometer for measuring flow speed and direction?

Hi, I'm trying to measure the steady state velocity field behind the wake of a bluff body in the wind tunnel. My uni is equipped with 4-hole cobra probes which is capable of receiving flow within a 45 degree cone of acceptance. As the base of a bluff body dominated with re-circulating flow...
29. ### Water nozzle

Good morning, I always walk on egg shells posting what is probably a redundant question on a forum. I have been reading for two days and there is a ton of physics information out there on the subject but most of it doesn't truly address the mechanics of what I am looking for. In a very...
30. ### How to find velocity of air at certain point if car is moving at certain speed (Fluid Mechanics)?

1. Homework Statement The shape of a car windshield is approximated in the figure below; its length is 2.0 ft and height is 1.5 ft. Obtain an equation of the windshield shape r as a function of θ, r(θ), in the polar coordinate system shown in the picture. When the car moves at 55 mph...