Flow Definition and 1000 Threads

  1. I

    I What is the equation for calculating average gas flow in a compressed syringe?

    Hi, I tried looking for similar topics but nothing really solved my problem. How can I calculate the average gas flow on a syringe that was compressed over time, if the starting and ending pressure and volume are known? I am guessing there must be an equation which can relate these variables...
  2. V

    Do electrons flow through a battery or is it something else?

    This is a confusing question. I am not sure if electrons flow through the battery from positive terminal to negative terminal against the electric field within the battery; or the electrons deposit on positive plate resulting in a chemical reaction that releases electrons at the negative plate...
  3. imagine2014

    Calculating Flow From Tank to Impeller

    Wondering if someone can help me with the following. If I have a sewage pump drawing wastewater from a tank, but there is a small distance between the invert to the impeller and the suction line, how much flow will enter through the opening, versus from the suction line. Can anyone explain in...
  4. A

    Inconsistent flow rate measurements of an engine diesel fuel

    I am measuring the volumetric flow rate of a diesel fuel using "Turbines" flow meter, both in the supply and return fuel lines of an industrial diesel engine (https://www.cat.com/en_US/products/new/power-systems/industrial/industrial-diesel-engines/18398034.html – coupled with a generator for...
  5. Y

    Heat circle -- Calculating the air flow needed across a condenser

    Hi! I need to calculate what air flow needs to flow across the condenser so that the heat emitted from the condenser is directed to the air. dT=10÷15 [C] COP =~3 According to the manufacturer's data the fan airflow is 0.67 [m^3/sec] and i need to check if i can use it. thanks
  6. G

    Which fan placement offers the most airflow for cooling electronics?

    I have two identical fans to cool electronics within an enclosure. From the two drawings/options, which option offers the most airflow? Thank you.
  7. A

    I Molten metal flow due to high currents

    It is mentioned in the book "Ampere-Neumann Electrodynamics of Metals", Peter Graneau, that Carl Hering in 1923 operated furnaces by passing high current through the molten metal pool. He observed molten metal flow due to the currents. How is the conductor motion explained?
  8. Teru123

    Heat Flow in a Pipe with integrated Sensor

    Hello, I have the following problem and hope you can help me. I have the setup as shown in the drawing. A pipe that is flowed through, and in the middle of it another pipe, but at the end of this branch is a sensor. Initially the fluid would flow, with a temperature of 25°C. If my thought is...
  9. C

    I Reynolds Number and Turbulence: Why Does Increasing Density Affect Flow?

    hi. I have a question regarding rheology. the Reynolds number increases when density of a fluid increases. so the flow becomes more turbulent. but I wonder why it is that the flow becomes more turbulent when density increases. why is that?
  10. L

    Best fan placement for optimal air flow

    I'm building a fume extractor for my workbench. I would like to hear your thoughts on the best placement for a fan so I get the maximal suction/airflow. I made a sketch with the general dimensions. The fan could be either in the A position before the filter or in the B position after the...
  11. P

    Bernoulli equation / fluid flow / finding height

    Hi, everyone! Doing some fluid flow/Bernoulli tasks. Ok, so the task is: «A hose with a radius of 0,035m is connected to a nozzle, which reduces the radius of the hose to 0,018m (2). The hose carries (qv) 0,0075 m3/sec and the totalpressure (3) in the wide section (1) is 211 kPA. The density of...
  12. C

    Question about flow from a nitrogen bottle

    I need to know how long a nitrogen bottle will flow for. It is 2.2 Litres 110Bar. I want it to flow at around 1 litre per minute to do an experiment. How long will it last? Sorry if this is a really dumb question.
  13. M

    Comp Sci How does Instruction 2 affect the updates in a flow chart for coding?

    I found this as problem 3/42 from here (copied below for viewing convenience). I'm a little confused about Instruction 2. The way I interpret it, upon the first loop, no evaluation is occurring, but instruction 1 now becomes "increase Box 2 by 2". So now the three instructions are 1) increase...
  14. P

    I Calculate the internal pressure of a tube based on flow rate

    I have pump of unknown flowrate pumping water through a tube of length L and diameter D. I know that the flowrate of water exiting the tube is X mL/min. I would like to know the internal pressure of the tubing, how can I calculate it? This all occurs at sea level elevation.
  15. M

    I Understand Poynting Density of Flow of Energy w/Weak Physics Background

    My physics background is weak. My search found lots of ## E \times B ## and ## E^2 + B^2##, often associated with ## \mu_0 ## and ## \epsilon_0 ##, but never divided by ## 4 \pi ## and ## 8 \pi ##, respectively. Could someone provide a reference? Or a derivation? Thanks.
  16. F

    What is the giveaway that region 4 is Rayleigh flow?

    answering part ccould someone explain each region of diagram. thanks. I've got parts a and b correct
  17. F

    Calculating Inlet and Outlet Times: c=451.8, u=135.5

    The answers given are 6.3s for inlet and 3.4s for outlet, which I was able to obtain by dividing 2000/c-u and 2000/c+u c=451.8 i calculated and u=135.5...
  18. T

    Low pressure, high velocity flow vs static pressure

    In this scenario, we have a compressible flow at 0.99 barA pressure and flowing at 300 m/s velocity and is released into 1 barA pressure. Point is, whether the flow can be released at 1 barA or not at the release pressure is higher than the pressure of the compressible fluid inside the tube. And...
  19. L

    I Surface tension and water (the smallest hole water will flow through)

    I am trying to find out what the smallest hole water will flow through. not a molecule of water, just water in general. Here is an example. I have a single walled cube that i 3d printed. When i put water in it, it leaks between the layer lines. I want to find out what the spacing between the...
  20. O

    Engineering Mass flow rate as a function of time

    At first, I inputted h(t), of which I solved for, into the mass flow rate formula. So it looked something like this, m-dot(t) = -(density)*[sqrt(g*(H-(g*d^4*t^2/D^4)]*(pi/4)*d^2 But I don't think that's right? Any thoughts?
  21. JD_PM

    A Cavitation: radius of a bubble for compressible flow

    The liquid-vapor mass transfer (evaporation and condensation) is governed by the vapor transport equation: $$\frac{\partial}{\partial t} (\alpha_l \rho) + \nabla \cdot (\alpha_l \rho \vec v) = \dot m^{+} + \dot m^{-}$$ In the incompressible flow case (constant density), it reduces to $$...
  22. Spinnor

    I Back of the envelope estimate, energy flow in a box of plasma

    Say we look at a spherical region of the sun where energy is mainly transported by radiation. Say this happens between some particular radius R and R + dr. Let the temperature at R be giving by T(r). At this particular radius let the gravitational acceleration be a reasonably well know function...
  23. casualguitar

    Modelling of two phase flow in packed bed (continued)

    Previous post linked here, where a model for the two phase flow of air through a packed bed was developed: https://www.physicsforums.com/threads/modelling-of-two-phase-flow-in-packed-bed-using-conservation-equations.1008754/ The first few comments on this new thread will be copies of the...
  24. MrS

    I Open channel flow: derive function for energy slope on friction?

    I want to determine the normal flow depth in a perfectly horizontal circular conduit. The system characteristics are known (Internal pipe diameter, Mannings roughness, Discharge). However, I am not sure how to calculate the normal flow depth. When using Manning's equation one can find the normal...
  25. N

    Mechanics of materials - shear flow in built up members

    Hello! I am new to mechanics of materials and I am very confused about the problem below. So the shear formula is: tau = VQ/It From the book (Hibbeler) I understand that Q is "y'A', where A' is the cross-sectional area of the segment that is connected to the beam at the juncture where the...
  26. JD_PM

    Understanding how to model a non-isothermal flow through a pipe

    For the fluid, I will use three conservation laws for mixture quantities (mass, momentum and total energy) and an additional equation for the void ratio (as explained in the paper "Modeling for non isothermal cavitation using 4-equation models"). If you want I can share the explicit equations...
  27. J

    A Why do the Navier-Stokes equations give us non-existent results for 3D flow?

    Navier-Stokes equations for 3D flow gives us wrong/non existent results, results that don't exist in nature. Does that mean equations that describe flow of fluids in a wrong way or how we can explain this situation? Because math is allways 100% correct, 2+2 is always 4, math is apsolute TRUTH...
  28. F

    Wheatstone bridge and conditions for current to flow between 2 points

    Hello, I was reflecting on the functioning of a balanced Wheatstone bridge circuit: Point C and D are at the same electric potential V (zero potential difference). Even if they are connected by an ideal zero resistance wire, current will not split at either node C or D to flow through that...
  29. F

    What Is the Best Method to Calculate Gas Flow Through an Orifice?

    Summary:: How to find gas flow through an orifice that links two vessels at different pressures. Two vessels containing the same gas are linked through an orifice with diameter ##d##. The pressure inside vessel 1 is ##P_1## and the pressure inside vessel 2 is ##P_2##, and let's have...
  30. O

    I Fluid force from a fluid flow vs. from a fluid jet

    In fluid flow (such as wind), the force exerted on a perpendicular surface is derived from kinetic energy and is ρAv^2/2. But in problems involving a jet of fluid that strikes a plate, the force is derived from momentum and is explained to be ρAv^2, lacking the 1/2 factor. Can someone please...
  31. stuartsjg

    I Compressible choked gas flow through an orifice -- Excel formula

    Hello, I normally get these things working but I am a bit stuck as i don't feel I am getting sensible answers... The problem is simple (!): Q: Model the flow through an orifice with an upstream/supply pressure of 301BarA where the downstream pressure is in the range 1BarA to 301BarA. The...
  32. A

    Coolant Mass Flow Rate Through Subchannel in Nuclear Fuel Assembly

    I am trying to find the mass flow rate of coolant through a channel within a hexagonal nuclear fuel assembly. I am given the specific heat of the fluid, the coolant inlet and outlet temperatures, the total power produced by a single fuel pin, the diameter of the fuel pin, the length of the fuel...
  33. L

    A fun, engaging and visual way of showing laminar flow for young kids

    I have been tasked by my fluid dynamics professor to create a 3 minute video showing and explaining laminar flow vs turbulant flow. It must be engaging and explain the concepts simply enough with no math. I will be re-writting this definition below to suite the needs ""Laminar flow occurs...
  34. S

    I Do electrons flow in an electrical circuit?

    The video on youtube on the above link seems to imply that electrons don't flow through a circuit. At 01:29 into the video, the narrator says that he used to teach his classes how electrons move through a circuit by using a clear plastic tube with a chain inside of the clear plastic tube. The...
  35. T

    Force on submerged plate perpendicular to flow

    Hey, I wonder how I can calculate the force of a plate that is submerged in water. I thought maybe the drag equation would be suitable for this with the drag coefficient set to 1.28 (https://www.grc.nasa.gov/www/k-12/airplane/shaped.html). But is implies the flow is according to the image...
  36. Dario56

    I Energy Flow From Battery to the Light Bulb

    When we connect tungsten filament light bulb to the battery, filament becomes hot due to electrons losing kinetic energy in the electric field inside of conductor. Heat is eventually converted to electromagnetic radiation making light bulb shine. Light energy comes from flow of electrons and...
  37. casualguitar

    Modelling of two phase flow in packed bed using conservation equations

    Previously, I have seen the derivation of the energy conservation equations for simulation of single phase flow in a porous media (a packed bed). These are the energy equations for the solid and fluid respectively: I understand the derivation, however, these equations will only work when the...
  38. F

    Fluid flow inside a cylindrical tank

    Hi, I´m quite lost and would appreciate guidance I have solved for 2 tubes using Bernoulli´s equation before, but now how does it change? Is it really going to rise water level inside? Why?
  39. Ophi-Siren-Kit

    Speed/Velocity and Volume Flow Rate of Viscous Fluids

    In my first attempt, I started off converting the radii of all three sections from centimeters (10, 8, 6) to meters (0.10 , 0.08 , 0.06), then used the VFR=Av formula to find the speed/velocity of section one. VFR== 0.063 m^3/s A== pi*r^2=pi*(10cm)^2=pi*(0.10)^2=pi*0.01 == 0.031415927 VFR/A=v...
  40. AJSayad

    Grad School Flow Simulation PC Build

    Hey everyone, I'm coming to the end of my Mechanical Engineering B.S. degree and I've been in the process of applying to mechanical and aerospace PhD programs. I want to do research in fluid mechanics; I have some expereience in hypersonics from a Research Expereince for Undergraduates NSF...
  41. Dario56

    I Work - Energy Principle Application to Fluid Flow

    In classical and continuum mechanics if we want to find equation of motion of the body we draw force diagram and apply Newton's 2nd law. In continuum mechanics, equation of motion actually refers to a special point of the body known as center of mass (COM) which can be proven by definition of...
  42. Dario56

    I Work - Energy Principle Application to Fluid Flow

    Work - energy principle states that work done by net force acting on the body equals change in kinetic energy of the body. We are talking about continuum mechanics. This principle is usually introduced in mechanics of solid bodies. For us to describe the motion of the body, it is enough to know...
  43. Y

    Help Understanding the Flow of Grease

    Homework Statement:: Conceptual Question Relevant Equations:: So say I have a grease pump with a line coming out of the pump to a T section. One line from the split goes to a component that is not that far away, while the other goes twice the distance from the split to get to the component. Am...
  44. D

    I Steam flow rate in 2-chamber steam engine system

    Our system of interest has a duct on the left and a piston chamber on the right that make the shape of the letter T rotated 90º clockwise. The smaller tube on the left is abbreviated as P1 has an unspecified length while the piston chamber is P2. The air in P2 heats up and expands while the...
  45. L

    I Is the current related to a path or to potential difference?

    The question is very simple: Is the flow of charge, or current, related to a closed path or there will be a potential difference without closed path to allowing the flow? I mean, If I have a battery that maintain 5V of potential difference through its terminal, I believe there is an amount of...
  46. L

    Earth grounded, where does the current flow?

    My questione are these: -If i have a voltare source (like a battery) that supplies a 5V voltage difference between its terminals, and there is a parth from positive to a resistor and then to ground, with negative terminal not connected: the current flow to the ground?( I believe because there is...
  47. RawPotatoes

    I Issue calculating water pressure due to the constriction of water flow

    For an experiment where I must be able to control the pressure i attached to a syringe a 'chamber'. The inner diameter of the syringe is 19.3 mm and i will fill water to 17 cm of the syringe bottom (i call this P1), the spout has a inner diameter of 2 mm and a length of 2 mm (i call this P2) and...
  48. M

    I Transmission through flow cell using small-angle x-ray scattering

    Hello, I plan to run an experiment using SAXS for in-situ solution phase reaction analysis. We will use a glass micro-fluidic chip due to experimental limitation reasons. I am looking for the optimal path length for these channels (fluid channel depth). My understanding is that we need to...
  49. R

    How does a pump trade head for flow rate?

    A pump’s power is a product of its pressure rise times volume flow rate. Commonly, a pump is specified by giving the pressure rise, or head, it can provide and the flow rate, such as in gallons per minute(GPM). But some pumps provide the user with a chart that shows how the pressure rise can...
  50. N

    How Do You Calculate the Flow Rate of Oxygen in a Pressurized System?

    I am trying to calculate the flow rate of O2 from a known volume 25 in^3. The cylinder will fill up to a maximum pressure of 140 psi in 11.26 seconds. Any help to determine the flow rate will be appreciated. Do I use Bernoulli equation to find the flow rate?
Back
Top