Help a College Student With Pipe Flow Calculations

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Homework Help Overview

The discussion revolves around investigating the effects of pipe roughness on air flow, specifically comparing the velocity of air in rough and smooth pipes set up in a wind tunnel. The original poster is attempting to calculate the air speed at the exit of the pipes based on experimental measurements and theoretical considerations.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • Participants discuss the measurements of inlet and outlet velocities, questioning the relationship between these velocities and the roughness of the pipes. There are attempts to clarify the implications of constant mass flow and the effects of friction on velocity. Some participants raise concerns about the measurement methods and the potential impact of the anemometer size on results.

Discussion Status

The discussion is ongoing, with various participants offering insights and raising questions about the calculations and experimental setup. There is a recognition of discrepancies in the results and a suggestion to retest with adjustments. Participants are exploring different interpretations of the data and the underlying physics without reaching a consensus.

Contextual Notes

Participants note constraints such as the size of the anemometer relative to the pipe diameter and the time limitations for retesting. There is also mention of the need for accurate pressure measurements and the challenges of achieving steady flow conditions in the experiment.

  • #31
You've got a core issue trying to measure the wind speed, which should not be chaging much within the pipes. If you could get a clear pipe, perhaps you could try using soap bubbles instead of pulsed smoke, but since your wind tunnel is drawing air (as opposed to blowing it), you'll need to make sure that the soap bubbles won't be a problem. You'll need to place some tape on the far side of the pipe at regular intervals so you can get an ideal of the speed of the flow within the pipe. Note that the bubbles will move at various speeds depending on location within the pipe, so you'll have to average out the results.

This is what you'd really need, a pulse smoke generator as shown in this video:

 
Last edited by a moderator:

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