Calculating Wave Amplitude & Wavelength in Water Pools

In summary, the gravity waves that are emitted when a mass falls into water are caused by the viscosity shear in the boundary layer of the water.
  • #1
jsurow
2
1
TL;DR Summary
How would we model/calculate the circular waves in a pool of water (wavelength and amplitude) from a mass falling into it from a given height, and from a fountain of water falling into it continuously?
How would we model/calculate the circular waves in a pool of water (wavelength and amplitude) from a mass falling into it from a given height, and from a fountain of water falling into it continuously?

Is there is a way to describe the initial configuration of the wave based on the stimulus. For example, what is the resultant wave amplitude and wavelength from a X kilogram solid sphere at a velocity of Y meters persecond hitting a Z square centimeter area of water, versus the stimulus being a single sphere of water contacting the same area of surface at a similar speed, versus a continuous stream of water as in a fountain hitting the water.

I'm guessing that the resultant wave is dependent on the energy of the object that hits the water surface, modified by some characteristic of the incident object and also of the ppol of liquid(water) that it falls into, such as its shape, viscosity, surface tension, perhaps even refractive index.
 
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  • #2
Maybe we can find a part analogy with the case of discharging a capacitor into a transmission line. Here the energy of the capacitor is transferred into a wave which travels away from it. I think that the capacitor discharges into the characteristic resistance (impedance) of the line, and the product CR will determine the time for the discharge to happen and the duration of the first half wave. So for a mass falling into water, maybe the energy is converted into a wave, and travels away from the centre. The energy is now spreading out over a plane 2D surface, so the energy density will decrease in proportion to distance, and the amplitude will decrease with the square root of distance.
As Lord Kelvin mentioned, water waves are not straightforward things to study.
 
  • #3
Welcome to PF.

The ripples that spread out across the surface are gravity waves.
https://en.wikipedia.org/wiki/Gravity_wave

Where a continuous stream of water penetrates a water surface, the surface is dragged down by the viscosity shear in the boundary layer of the water. Once the system is stable, no more gravity waves will be radiated.
 
  • #4
His areas of research are perhaps a little different, but I'll page @Dr. Courtney to see if he has worked with gravity waves in his impulse research...
 

Related to Calculating Wave Amplitude & Wavelength in Water Pools

1. How do you calculate the amplitude of a wave in a water pool?

The amplitude of a wave in a water pool is calculated by measuring the vertical distance from the equilibrium position (the still water level) to the crest (highest point) of the wave. This can be done using a ruler or any other measuring device. The amplitude is half of the total wave height, which is the distance from the crest to the trough (lowest point).

2. What is the formula for calculating the wavelength of a wave in a water pool?

The wavelength of a wave in a water pool is the horizontal distance between two consecutive crests or troughs. It can be calculated using the formula: wavelength (λ) = wave speed (v) / frequency (f), where wave speed is the speed at which the wave travels through the water, and frequency is the number of waves that pass a fixed point per second.

3. How can you measure the frequency of waves in a water pool?

To measure the frequency of waves in a water pool, you can count the number of wave crests that pass a fixed point in a given amount of time. The frequency (f) is then calculated by dividing the number of waves by the time period. For example, if 10 waves pass a point in 5 seconds, the frequency is 10/5 = 2 Hz.

4. What tools or instruments are commonly used to measure wave amplitude and wavelength in water pools?

Common tools for measuring wave amplitude and wavelength in water pools include rulers or measuring sticks for amplitude, and stopwatches or timers for frequency measurement. For more precise measurements, wave gauges or sensors can be used to record the wave characteristics electronically. High-speed cameras can also help in analyzing wave patterns and calculating wavelengths.

5. How does water depth affect wave amplitude and wavelength in a pool?

Water depth can significantly affect both wave amplitude and wavelength. In shallow water, waves tend to slow down and their wavelengths shorten, while their amplitudes may increase due to the interaction with the bottom. In deeper water, waves travel faster and have longer wavelengths, with amplitudes that are generally smaller compared to shallow water waves. The relationship between water depth and wave characteristics is governed by complex fluid dynamics principles.

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