Jet Definition and 327 Threads

This is a problem for a fluid dynamics class I'm in. My current approach is to use a conservation of mass approach and say that the d/dt(momentum in the cart) = momentum into the cart. This leads to (u is speed of the cart, V is volume J is jet velocity, A is cross sectional area of the jet)...

Hi PF! Can someone help me understand the development of a laminar jet flow? Perhaps @Chestermiller and @boneh3ad have some advice? Thanks!

Homework Statement A water jet hits a wall and splits into two streams (see attachment). The jet carries 3kg of water per second. The cross-sectional area of the flow at (2) is A = 2*10^-3 m^2. The average velocities at the outlets are V2 = V3 = 1m/s What is the net vertical force exerted by...

This is something I do not know how to explain. Although velocity decreases due to friction with ambient air, momentum should be conserved and, therefore, it entrains mass. What is the reason that momentum should be conserved?

Hi Does someone know realistic numbers that i can put in this equation so i can calculate the force? Ty maximilian Popelier

Hi, do you guys got information about g forces on a jet and maybe exercise and ansers where you need to calculate the g force in a turn? ty for the help Maximilian Popelier

Hi guys I'm making a project about jet engine. I need to write 10 pages of the mechanical part of a jet engine. I already did it for physics. What can i talk about. I need formules en stuff in the 10 pages Ty for the help guys! Max

Hi, I need help I got a project for school about jet engines. They say bysubstitution of equations 5.1, 5.2, 5.5 and 5.6 butI don't know the steps how i get t0 the last formule. Thank you Maximilian Popelier

The Problem Statement I have a jet entering leaving a nozzle at ui into an ambient fluid with ue = 0 I am trying to equate the rate of momentum diffusement (or spread) to the shear forces caused by ue -ui I understand that the rate momentum diffusement is are equated by empirical K- values...

I saw a video recently describing the lift in terms of pressure. It stated that the Coanda's effect is important. That is the tendency of a fluid jet to flow a curved path. It stated that there is high pressure above the top of an air foil and low pressure below so the air drops or gets...

The surface of the Earth is moving approx. 1000 miles per hour at the equator. Which means, excluding natural wind and especially hurricanes, the air is also moving about 1000 miles per hour along with the surface, or the central areas of the Earth would be stripped of just about...

I'm wondering about theoretical maximum velocities of supersonic electric aircraft. I think the fastest demonstration of any type of aircraft has been close to mach 10. This was done using a rocket engine, so propulsion would not be limited by air characteristics as much as a fan's propulsion...

I am stuck on C and D and E, any help would be appreciated! The speed of the water (which is calculated in B) is 4.43 m/s For C I think it might be law of conservation of momentum or use the formula P=(1/2)*rho*A*v^3 with P=FV and possibly F=ma? I think D is just STUVA (s=ut+(1/2)at^2) where...

Here's a really complex & difficult question... Satellites orbit Earth in the upper thermosphere. Could a jet engine (not a rocket) produce enough thrust to move a small craft? The reason I'm asking is because it most certainly would produce "some" thrust in low orbit. The atmosphere extends...

Does lightning heat air 5 times more the the suns surface? If so can a hybrid lightning jet engine work, as lightning heats up air, more then fuel can? Americas 5th gen jet fighter can travel 3* more then enemy jet's. That means it's a hybrid engine right? Compressed air heated sees the air...

Hi, I recently did an experiment whereby we investigated the velocity distribution of air expelled from a round nozzle whose diameter, D, was 30mm. We have been asked to calculate the volume flow rate at distances of 2D, 6D and 10D along the centreline. We found the flow rates to INCREASE...

I am trying to calculate at what pressure and speed water from a high pressure water jet will hit an object 100 millimeters away from the nozzle opening, but i can't figure it out. The nozzle will be used at approximately 100 meter below sea level in salt water. Its a circular nozzle with a...

Hello! I've just received information that there may be a requirement to cut some carbon fiber fabric on the water jet machine in our lab. The party that wants the cutting done, requires an option that's quicker than using shears to cut it. That's pretty much all the information I have at the...

Hi , I'm new to CFD. I'm modeling a parking ventilation system in ansys CFX. I'm having some trouble modeling the jet fans . I went as follows. I created a fresh air inlet (Opening BC), an exhuast outlet (outlet BC) and in the middle I distributed jet fans .The jet fans are modeled as sub...

Hey Guys, I want to verify the exhuast design of a car park ventilation system on Ansys Fluent. Basically, I have jet fans distributed throughout the parking displacing air towards a certain point where I will extract it . How would you go about modeling the boundary conditions in this...

Why does the polar jet stream flow counter-clockwise around the Earth (as viewed from the north pole)? It seems that since the air at the north end of the Ferrel Cell and the south end of the Polar Cell rises, the Coriolis effect would cause a circulation in the clockwise direction.

i want to calculate the force of a water jet i know the velocity,13,6m/s mass or volume/s=52,6kg or dm3/s the pipe has an area of 2,3dm and the gained area by flying out the pipe is 3,4dm i want to know the force it creates by hitting for example a way, how do i calculate that

Consider a case- Force excerted on a stationary flat plate held normal to the jet. The Jet strikes on plate (see fig.) Which is smooth hence the exit velococity of jet = entering velocity of jet. According to theory. The fore is applied on plate due to change in momentum of jet. But my doubt...

I can never derive the prolongation formulas correctly when I want to prove the Lie group symmetries of PDEs. (If I'm lucky I get the transformed tangent bundle coordinate right and botch the rest.) I've gone through a number of textbooks and such in the past, but I haven't found any clear...

Hi! I'm a high school student, aspiring to pursue a career in Astronautical Engineering. I always try and ponder on questions about everyday aerodynamics and physics. So, here's a question from you from an aspiring scholar. It is known that, at high velocities, pilots in super-sonic jet...

Well this really complicates matters :frown: Turkey Says It Shot Down Russian Warplane Near Syria Border http://www.bloomberg.com/news/articles/2015-11-24/unidentified-warplane-crashes-in-syria-near-turkish-border

http://www.bbc.co.uk/news/uk-england-cambridgeshire-34593948 Thank you for your service. RIP. A US Marine Corps pilot has died in an F-18 jet crash, close to an RAF base. The jet came down on farmland in Redmere, near Ely, Cambridgeshire, with the alarm raised at 10:30 BST. The Hornet...

Hi all, my first post on here and just wanted to check something I'm working on for a project. The project is to use a pump to create a jet of water to manouvre small boat. I have found a formula to work out the jet reaction force in a fire fighting textbook which gives: R = 0.157 * P * d^2...

http://www.cnn.com/videos/tech/2014/10/30/pkg-future-of-travel-jet-engine-leap-plane.cnn

A jet flying directly over you at an altitude of 3300 m produces a shock wave. The angle of the shock wave is 43 degrees. How long will it be until the sonic boom reaches you? How far does the jet travel during this time interval? I know that I can figure out the second part of this problem if...

Homework Statement The apparatus or "jet pump" used in an industrial plant is constructed by placing the tube within the pipe. The velocity of the flow within the 200-mm-diameter pipe is 2 m/s, and the velocity of the flow through the 20-mm-diameter tube is V = 37 m/s . The fluid is ethyl...

This is a simple question that I should've known, but I'll ask. Fluid jet with density $ flows with velocity V1 before it strikes a block, then goes in two perpendicular directions, like left, right with the same velocity V2 in opposite directions. Find the force on the block. My try: The...

I really can't seem to wrap my head around why the specific impulse on a rocket is so much lower than that on a jet. I know a jet engine has a larger supply of oxygen, but I don't see why that has such a huge effect. I also know exhaust velocity plays a large part, but I would have thought that...

Hi there, I have some questions about plasma I wonder is it possible to use another gas (not inert gases) ?. and where i can find more information of plasma jet ? because it's almost have a copyright. Thank you.

"The static pressure at all points within a free jet of a liquid is uniform throughout and is equal to the pressure surrounding the jet " I am looking for an explanation to the above statement. If we consider a vertical stream of a liquid flowing through an orifice at the bottom of a liquid...

Homework Statement At an air show, a fighter jet does manuevers past the crowd. Your increible hearing notes that the frequnecy of the sound coming from the jet engine drops exactly by one octave when it is approaching you to when it is directly above you (not moving relitive to you). How fast...

Hi, I've got this water circulation system. Diagram attached: http://postimg.org/image/wmf2hql6p/ In the upper container jets of water come out from the pipe due to the small holes I have drilled into the sides. I would like to know how I can work out the impact pressure on surfaces that may...

I've read that the total forward force on an engine is given by a change of momentum which is written as ##P = \mu_{fuel}v_{0} + \mu_{air}(v_{0}-v) ##, where ##\mu_{fuel}##, ##\mu_{air}##, ##v_{0}## and ##v## are respectively the rate of decrease of mass of the fuel being burnt, the rate which...

As a jet engine travels through the sky and picks up speed ram air increases the air pressure at the air intalk of the engine. How many mph does the engine have to be going for ram air to 2 atmospheres = 29.4 psi? At what speed in mph = 3 atmospheres? 4 atmospheres? Is this a linear or...

Here is something I read on a Wiki article: "Scientists are investigating ways to harness the wind energy within the jet stream. According to one estimate, of the potential wind energy in the jet stream, only 1 percent would be needed to meet the world's current energy needs. The required...

Hello. Do you think the idea of placing the jet engine at the front is plausible? Why? Why not? Thanks Yrjosmiel

Homework Statement Apologies for the vague title but I'm not sure how else I could word it, also this isn't really a homework question per se however I'm not too sure where else to ask it. I think it would help if i set up a scenario. Say there was a pipe that released a fluid to a mass...

Milky Way core drives wind at 2 million miles per hour -- ScienceDaily http://www.sciencedaily.com/releases/2015/01/150105182525.htmThe article graphic shows three distinct flows of material... One moving towards earth One moving away from earth And One with no net motion along the line of...

Hi all, Recently did a lab experiment where we had a nozzle pointing vertically upwards at a flat plate normal to the direction of the flow of air. The plate had a spring gauge on it so that the force of the air on the plate could be measured. The plate was moved to various distances above the...

I was thinking about the working principle of propeller aircraft (piston engined) during some dark night hours with nothing to do... Mostly because of flight simulator video games hahaha... Basically for the piston engined propeller aircraft (P-51 Mustang) to move forward, the propeller must be...

hi every one i'm alireza from sampad high school (iran) first, excuse me for my bad english i want to have a research about plasma jet ... i know nothing about plasma and plasma jet but my subject is about it ! i bought a book (name: " Hans C. Ohanian " ) and want your opinion about my...

If in the bottom of the bucket with water we made a hole, then water flows out of it. Bucket with water is the system with ##m(t)##, thus we have to use equation: ##m(t)\frac{dv}{dt} = F + u\frac{dm}{dt}##. Where ##u\frac{dm}{dt}## -- is jet reaction force. But, I think the jet reaction force...

Hi guys, I'm trying to find info with respect to twist angles of a turbine blade (for airplane engines, let's say)... I read somewhere on the forum that it's typically 0-20 degrees. I'm trying to look for quoted sources though or at least second opinions on that matter.

I am to choose a certain type of jet fan in a parking garage. Looking at a spesific one, what I'm having a hard time considering is the noise it generates - 78 dB (A) at 3 m - and whether it would within acceptable limits? This is a fan that you would pass underneath walking to or from your car...

Homework Statement What would be the effect of calculated value if: a. Jockey weight is in error by 1 g? b. Distance from vane center to pivot point is in error by 1 mm? c. diameter of nozzle 0.1mm different from actual nozzle diameter. Homework EquationsThe Attempt at a Solution as the error...