Questions tagged [fluid-mechanics]
Questions relating to fluids at rest (fluid statics) or the forces and effects of fluids in motion (fluid dynamics).
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Astute-class submarine nose module shape
The nose module features a continuous ridge running along it's side. The rest of the hull has the typical "cigar" shape as other sub designs.
(Q1) Does the "ridge" have a proper ...
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Reduced flow rate due to Hydraulic effects
Can anybody help me with papers or studies on reduced flow rates when pumping fluid through multiple pipes in a network due to hydraulic effects compared to those achievable when operating ...
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Velocity value in a pipe junction when we're applying the energy equation
I'm trying to understand how to apply the energy equation at a junction of 3 pipes. For example, when we are considering points A and D, should we consider that velocity at point D just before the ...
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Can the volume of fluid flow affect a strain gauge's measurement accuracy?
I have two machines for testing solenoids, one new and one old.
When a bypass is connected to both hoses (the input hose is connected to the output hose), I get ~1:1 for the input output pressure; the ...
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Will a lid hovering above bursting air bubbles catch smog particles
The bubble bursting phenomenon goes like the above describes:
At 1, the air bubble is under water.
At 2, the bubble emerges above the surface, with a thin film of water rising to keep it from bursting....
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Casting and the pressure of the metal
Background
A gold casting process is explained here:
The casting metal is melted in a special casting machine that is programmed to insert the metal under vacuum into the flask at the right time, ...
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Where should I restrict the flow of a pump?
I am using a 1/2 hp sump pump to provide flood coolant to a CNC milling machine. The sump pump has a 1.5" outlet. The milling machine already has a 1/2" adapter and manifold which connect to ...
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Metal casting simulation and the solidification analysis
Casting process analysis
Mold filling affects the quality of a casting. The fluid flow phenomena are closely related to the casting quality and surface finish. The dimensional accuracy of a casting ...
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How to determine the slope for the gravity flow of highly viscous fluids (eg. gum)?
I am looking for a method to determine the slope of the pipe required to maintain a gravity flow for highly viscous fluid.
The Hazen-Williams equation for gravity flow is applicable for liquids which ...
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How can I calculate the pressure in a pipe?
I am an engineering student designing a pipe system for a fluid flow and I calculated everything including the pressure loss. Now I have to choose a pipe material and pipe thickness for the piping ...
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How could we aproach development of touchscreen with morphing surface or morphing keyboard?
There is this technology of braille e-readers. It is relatively simple and reliable but it never had much commercial success probably because small customer base.
In past a company called Tactus tried ...
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Orifice flow meter equation applicability, modeling leak flow
I am trying to determine the correct equation to model ideal gas flow rate through an orifice as a function of pressure. The equation below I found in Marks' Handbook for Mech Eng 8th Ed, p. 3-64 ...
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Total dynamic head calculation of a submersible pump with different dia pipes connected to its discharge
I have to install a submersible pump for pumping ground water to irrigate land. I have six inch diameter metal pipe already available that I plan to use in the project. The pump delivery is 5 inches ...
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Modeling a two tank system which will be regulated using a single valve
This is a mix between a physics and controls engineering question. At first I thought it was mostly a physics question and I therefore asked it at physics stack exchange. But they said this was mostly ...
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Why does CFD over predict shockwave in comparison to wind tunnel?
I ran a CFD simulation of Mach=0.85 flow over an aerofoil and noted that my Cp (coefficient of pressure) plot over predicts the shockwave in comparison to experimental data?
Can someone please explain ...
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What happens when electrolytic process rotameters are swapped for a much bigger one?
electrolytic process rotameter were swapped for much bigger rotameters. Inlet pipes are the still the same. What effect does the bigger rotameter have in the concentration of catholyte in the cell?
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Is it more difficult to cut a single steel column, or a wire of the same width made up of several skinnier, individual wires?
Would it be more difficult to cut a single 15.75" column of solid galvanized steel, or a 15.75" wire made up of 5,282 individual strands, or would it be the same? The wire in question is the ...
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Can someone explain why this sprayer arm wouldn’t simply accelerate to infinite angular velocity?
If mass-flow-rate * velocity = force, then this sprayer arm (frictionless and horizontal to gravity) should accelerate to infinity being the force remains constant. I am assuming I am missing ...
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How to estimate air velocity at turbine in turbojet?
I am designing a small turbojet. I wanted to know how to calculate the air volume expansion to predict the outlet velocity of air towards the turbine. Theoretically, I wouldn't know the flame ...
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Shaped charges and fluid dynamics
Watching this video https://twitter.com/Rainmaker1973/status/1713599092968787987 of objects being dropped into water and the resultant shape of the displaced fluid reminded me of videos showing how ...
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How to calculate mass flow rate at the Multiple Channel Outlets?
I have a basic question regarding the calculation of mass flow rates of a channel with multiple outlets. In the scenario depicted in the image below, we have a single inlet with a mass flow rate (m1) ...
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How to convert the Differential pressure in Pa to flow rate?
I am using SDP32 sensor and got the differential pressure value of the air. I want to convert this value to flow rate. What is the equation for that?
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Variable inlet velocity implementation in ANSYS Fluent
I'm trying to perform 2D analysis for a steady laminar incompressible flow through a horizontal channel with a height of H (m) and length of 2H. The boundary conditions is of the form:
$u=\frac{3}{2}...
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Fluid dyanmic - flow in a pipe
Dear fellow engineers,
I have a question regarding a fluid dynamic problem which I have sketched out. The initial fluid velocity is 1.5 m/s at 1.5 bar and the fluid is water. The pipe line has a ...
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Hydrographic Survey Problem
I have been trying, but I can't figure out how I should solve this using the area velocity method. It is the only method as our professor taught us.
Any help would be appreciated.
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Effect of pipe size on water flow rate in municipal water system
am expanding my house and the town is requiring us to increase the size of the water line from the street from 3/4 inch to 1 inch diameter.
intuitively i understand that a bigger pipe results in more ...
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Will hot object near ceiling vent create more draft?
As in the picture, we have a room with vents at the bottom to let cold air in and at the top to let hot air out. Normally the air flow is limited by the temperature gradient (correct me if I'm wrong). ...
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How to fluidize sand inside a 55gal Steel Barrel?
Looking for recommendations on how to make a fluidized sand bed inside of a 55 gal steel barrel. I've seen many examples of it done with pipes but I am worried about the evenness of the fluidization. ...
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What does a dynamic-pressure loss coefficient of more than 1 mean (for eg air going through bend)?
Air flow (eg in a duct) has a dynamic pressure, and when the air flow goes through e.g. a 90°-bend the bend has a dynamic-loss-coefficient.
The dynamic-loss-coefficient is used to calculate the total-...
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How can I make sure that my outflow is the same as my inflow?
I have a basin that is 110 mm wide, 200 mm long, and 15 mm deep. The walls are 2 mm thick. It has water being pumped into it at a rate of 0.1078 gpm from one side. In order to ensure that this pan ...
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How much air pressure is needed to push liquid out of a tank
I want to use compressed air to push diesel out of a 100 gallon rectangular tank for fueling equipment. Tank is 24” tall with a 30’ 3/4” hose reel on top. Height of the nozzle would be 6’ ft from the ...
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Calculate heart valve flow rates over time. What formulas are involed?
I'm trying to program a simulation of a human heart which I want to produce results close to the following:
(Source: https://en.wikipedia.org/wiki/Cardiac_cycle#/media/File:Wiggers_Diagram_2.svg)
For ...
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Unable to validate hypersonic flatplate case in DSMC SPARTA
I'm trying to learn a software called DSMC SPARTA. I'm validating the hypersonic flatplate case mentioned in one of the tutorials on the website (Page 17). This was my test case:
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How do I determine the moment of force that would have to be applied to the shaft to open the gate in this question on fluid statics?
I am presently studying fluid statics from Munson's textbook. I do not understand part (b) of example 2.6. The full question is as follows:
GIVEN The 4-m-diameter circular gate of Fig. E2.6a is ...
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Question About Dimensions and Figures Surrounding A Pressurised Nitrogen Canister
I need a nitrogen gas canister that will nitrogenate a beverage much like how SodaStream carbonates. Here are some approximate numbers:
The beverage to nitrogenate is 600 - 1000 mL
I want to be able ...
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How does this fluid-fill stop mechanism work?
I bought an interesting shaped water fill-stop valve from ebay a while ago. Very convenient form factor, even though there was some forward pressure requirement.
I want to now make a custom version ...
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Split tubing assembly
I am designing a tubing (TPE) assembly that splits a single inlet line into either four or eight outlet lines. The goal is to achieve an approximately equal flow rate of mildly viscous liquid at each ...
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Magnetic Float Switch inside Filling Nozzle
I want to design a Liquid Flow Nozzle that has a Magnetic Float Switch inside, The Idea behind is that there is a system that has a Manifold with 10 to 12 Nozzles connected with it.
Now I want to fill ...
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I'd like to create a column of smoke that goes as high as possible. Is there a fan or configuration of fans that is best?
Budget ~$5k
Current setup:
2x 20k cfm water-based smoke machines facing each other 6' apart blowing across the top or bottom of a fan or set of fans. I was hoping there could be a way to get a vortex ...
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Why are Reynolds Stresses time-varying?
The time-averaging operator definition gives us
$$\overline{u_iu_j}=\lim_{T\rightarrow\infty}\frac{1}{T}\int_{0}^{T}u_i(x,t)u_j(x,t)dt.$$
From my understanding, this should mean that the Reynolds ...
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Darcy-Weisbach: Static or Total Pressure?
Does the Darcy-Weisbach equation give the change in static pressure or does it give the change in total pressure (static plus dynamic)?
I’m assuming here that the static pressure includes the ...
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Can I use water flow meter for measuring flow of glycol accurately. Why yes/no?
I have water flow meter and I was wandering if i could reuse it in new project for glycol.
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Compression phenomenon in Axial flow compressor
It is quite difficult for me to visualize how axial flow compressors work, as in, how air gets compressed by just flowing through a series of aero-foil shaped stator and rotor blades. How and where ...
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How is flow energy different from kinetic energy of a flowing fluid in a control volume?
While I am studying about Mass and Energy analysis in Control volumes in Cengel and Boles I came a across a term called flow energy. The textbook definition that was given is as follows - "The ...
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What is the ideal oil for an electric razor?
As in the title, what is the ideal oil for an electric razor, and why? I might add that the electric razor will only be used at room temperature.
What oil would an engineer select for their electric ...
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Heat losses of warm fluid in a cold pipe
I'm looking for a way to calculate/estimate heat loss in a fluid flowing trough a pipe for a length (l) and travel time for the fluid (t). The flow is intermittent and the initial pipe temperature (...
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What's the hydraulic loss of this overflow?
Consider the following image:
what we see is are upright pipes into a water vessel, upper end of the pipes above the max. water level. Water is pumped into the pipes from below. We need to consider ...
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Finding the time taken for pressurised tank to reach 1 atm (Exam Prep)
A gas tank has an internal volume of 0.3m3. It is filled with helium pressurized to 32 bar (absolute). The gas tank is in thermal equilibrium with its surroundings and so the gas is at a temperature ...
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Calculating Pressure Loss (K Value) of Pipe Bends at varying Angles
I am analyzing the total pressure loss of a run of pipe that has several pipe bends at varying angles (30, 60, 45, 90, etc. degrees). Reading through CRANE: Flow of Fluids Through Valves, Fittings, ...
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Working of an eductor
Am currently learning P&ID diagrams. I came across the term ‘eductor’ and I’m trying to understand its working. Apparently, it’s different from an ejector in the sense that it draws the fluid in. ...
