# What is Air velocity: Definition and 18 Discussions

Characterizing how air is introduced to, flows through, and is removed from spaces is called room air distribution. HVAC airflow in spaces generally can be classified by two different types: mixing (or dilution) and displacement.

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1. ### Calculating turbine RPM in a pipe with known air velocity and diameter

Hello, I am trying to calculate the turbine RPM for a turbine in a closed pipe. I know the air velocity and pipe diameter. Can this be done?
2. ### A Can high air velocity in vacuum system create "freezing" of the pipe?

Hi folks, very simple question, but have not been able to find an answer: Assume a vacuum pump pulls air through a pipe. Also assume that within the pipe run, there is an area with reduced cross section, creating a temporary increase in air velocity. Also assume the air is very moist, and is at...
3. ### Calculating Surface Shear Stress in a Boundary Layer with Given Velocity Profile

Homework Statement If the velocity v of the air in a boundary layer having a dynamic viscosity of 18x10-6 kg/ms is given in terms of the distance y from the surface by v = ay + by2 where a and b are constants, calculate the surface shear stress if at 1.5 mm from the surface the velocity is 75...
4. ### Is there a way to find the velocity of air in a flute?

Homework Statement I am working on a math investigation which involves the physics of the flute and I can't move on unless I find an equation for the change in required velocity of the air stream to produce different frequencies. I have a feeling I might have to abandon this idea and do...
5. ### Calculating the velocity of a molecule

Hi, I'm stuck on a problem. I have this function that represents the velocity: f(v)=v2e(-mv2)/(2kT) T is the temperature and equals 293.15K m = 4.65 .10-26 kg k = 1.38 .10-23 J/K The problem wants us to find the derivative of the function. I found: df/dv= (2v)...
6. ### Air velocity inside a pipe (natural convection)

Hi guys, I'm doing some research in papers and literature to solve this problem but I've not found anything useful. I want to know the air velocity inside a pipe by the only effect of natural convection. I've attached a picture of the system right here: I hope you can help me to find the...
7. ### Maximum air velocity through a hole

this should be easy. suppose i have a very large spaceship holding a tremendous volume of air at 14.7psi with a density of .0023769 slug/ft^3. i put a hole in the side of my spaceship that is 6" in diameter which vents to the vacuum of outer space. what is the velocity of the escaping air? i did...
8. ### Blocked pipe = increased air velocity?

Blocking the intake of an air flow station I built results in the FPM shooting up along with the vacuum. ie: wide open both ends 4" pipe with inline fan reads . 5" wc / -190 pa / 3700 fpm on instruments monitoring intake pipe. Blocking the intake increases both the vacuum to -470 pa and...
9. ### 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...
10. ### Reduce mass flow rate may increase air velocity?

Hi, I used a blower to flow air across an open duct through a nozzle. By using a gate valve, the mass flow rates were controlled. I took measurement in 3 different locations along the ducts. But, why by decreasing the mass flow rate, the air velocity was increased? It is just happened for the...
11. ### Calculating Air Velocity in an Elastic Collision

F=force, m=mass, a=acceleration, V=Volume, D=Density, dv/dt=(change in velocity)/(change in time) F=ma D=m/V m=VD a = dv/dt F=VDdv/dt = Volume * Density * (change in velocity) / (change in time) = (Volume of Air Moved) * (Density of the Air) * (the final velocity of the air)...
12. ### Intake Runner Air Velocity Question

looking at the 2 intake ports in head and i'm looking at 2 bbl intake runners. i would say if i blew foam into runner and took it out the cross section would be smaller than pair of ports at the cylinder head. questions: does this speed up the air? if i keep the runner 'full size' up to...
13. ### Air velocity from small aperture

Hello. I am designing a drying mechanism for a window. Basically air is taken from the atmosphere by a vacuum pump and is ducted to a small width aperture. The aperture would be 18 inches long and as thin as we can make it (millimeters). Inspiration for this design is from the Dyson hand dryer...
14. ### Calculating Air Velocity in a Duct with a Consistent Cross-Sectional Area

Suppose I have a straight, frictionless duct, with consistent cross-sectional area, and air is flowing straight through and exiting into a free stream. A fan at the beginning of the duct draws stagnant air at atmospheric pressure, and then the air exits the end of the duct into another room also...
15. ### What is the air velocity from a tyre pumped to 200 kPa?

Can anyone tell me what the velocity of air coming out a valve of a tyre pumped to 200 kPa would be? What equations to you use?
16. ### Maximum air velocity in ambient conditions?

Maximum air velocity in ambient conditions?? Masters what is the maximum air velocity that can be achieved in ambient condition?? In the throat of sonic nozzle it attains sound velocity. Is it possible to attain more? If yes how?? thanks
17. ### Air Velocity vs generated Pressure

I have a simple question, can anyone please help. It goes something like this: if wind is blowing at a velocity of 80 mph against a 2" X 2" plate, how much pressure (or force) is brought upon the plate? would appreciate the formula, if any. Thank you. Farid
18. ### Air Velocity: 3in Tube vs 2 1.5in Tubes

Say you have a 3 inchs diameter tube and u have a machine that sucks air from it with force A. Then you have 2 tubes that is binded together each with a 1.5 inch diameter and have the same machine sucks air from it with force A also. Would the air velocity of the 3 inchs tube be slower...