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Disdrometer Love Rain on My Parade

Disdrometer Love Rain on My Parade. By Josh Molzan Steve Gronstal. What the Heck is a Disdrometer. An instrument to measure the drop size distribution falling hydrometeors Three main types: Video disdrometers Acoustic disdrometers Impact disdrometers. An Impact Detector.

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Disdrometer Love Rain on My Parade

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  1. Disdrometer LoveRain on My Parade By Josh Molzan Steve Gronstal

  2. What the Heck is a Disdrometer • An instrument to measure the drop size distribution falling hydrometeors • Three main types: • Video disdrometers • Acoustic disdrometers • Impact disdrometers

  3. An Impact Detector Momentum transferred: • P = Mass * Velocity • Mass = f(size) • Velocity = f(size) Basically, Size is EVERYTHING

  4. Creating Our Disdrometer

  5. Our Disdrometers

  6. The piezoelectric device:What is it and how does it work? • Piezoelectricity is the ability of some materials to generate an electric field or electric potential in response to an applied mechanical stress. • Basically, the harder you push it, the bigger the voltage.

  7. But its sooo small • Is the detector big enough to accurately measure the rainfall distribution?

  8. Rainfall Rate

  9. How many drops hit per second?

  10. So how many drops hit?

  11. Experiment 1 Examining the signal of a drop on each sensor

  12. The Good (Head 3)

  13. The Bad

  14. The Ugly (Head 1)

  15. Analyze lots of drops per detector

  16. Experiment 1:Results

  17. Experiment 2 • Examine how much size matters. • Drop 4 different size drops onto our favorite detectors. • Find the relationship between Voltage response and drop size.

  18. Creating Drops

  19. This Signals (H3, Buret)

  20. Analyzing the Signal • Damped Harmonic Oscillator • (i.e. a spring)

  21. Results…. But… What does it mean?

  22. Voltage Relationships? • Possibility One: • Model our system using Electrical Potential Energy • V α KE? • Possibility Two: • Model our system as a spring. • V2α KE

  23. Electric Potential Energy • Assumptions • The KE of the raindrop is completely transferred to the detector • The initial KE is then converted into Electric Potential Energy. • The Voltage Change acts like a pt charge moving in an electric field.

  24. Is V α KE??

  25. Energy of a Spring • Assumptions • The KE of the raindrop is completely transferred to the detector • The initial KE is then converted into Spring Potential Energy. • For Piezoelectric materials, a change in stress results in a change in potential • Capacitors have the same relationship!

  26. Is V2α KE??

  27. Log D vs Log A

  28. Diameter3 vs Amplitude2

  29. Conclusion • After analyzing 250,000,000 lines of data, our results indicate Kinetic Energy is proportional to Potential Squared. • More data points are needed to confirm the relationship between particle diameter and voltage response! • With more work, a piezoelectric transducer will make a decent disdrometer.

  30. Future work to do: • Experiment with smaller drop sizes (< 2mm diameter). • Experiment with drops at terminal velocity. • Experiment with an oscilloscope that can handle larger voltages. • Determine the voltage variation due to drop impact location. • Move analysis to real-time…..

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