Uncovering the Secrets of Water Slide Physics

[Spiffyline153]

TL;DR

I'm a researcher hoping to look at some papers on the technical aspect of water physics on a water slide. Does anyone have resources or pointers for me?

I'm a researcher hoping to look at some papers on the technical aspect of water physics on a water slide. Does anyone have resources or pointers for me? Essentially, I'm trying to find the optimal amount of water needed to propel a passenger down a standard straight water slide, but I don't know where to start. Please help me out!

 

[berkeman]

Welcome to PF.

Summary: I'm a researcher hoping to look at some papers on the technical aspect of water physics on a water slide. Does anyone have resources or pointers for me?

I'm a researcher hoping to look at some papers on the technical aspect of water physics on a water slide. Does anyone have resources or pointers for me? Essentially, I'm trying to find the optimal amount of water needed to propel a passenger down a standard straight water slide, but I don't know where to start. Please help me out!

Try a Google search on water slide hydrodynamics -- I got lots of good hits. Try that search and let us know what you find.

 

[Dale]

the optimal amount of water

I don’t know about water, but I do know about optimization. The first thing you will need is to decide on your metric for determining “optimal”. In your mind what makes one setting better than another?

 

[berkeman]

I don’t know about water, but I do know about optimization. The first thing you will need is to decide on your metric for determining “optimal”. In your mind what makes one setting better than another?

Good point. I did a Google search on Waterslide Accidents and got lots of hits. So "optimization" would seem to need some consideration of safety, not just maximum speed...

 

[Baluncore]

Essentially, I'm trying to find the optimal amount of water needed to propel a passenger down a standard straight water slide, but I don't know where to start.

You start at the top, and let gravity propel the player.

Does the water propel the player in any way, or is it just there to lubricate and cool the contact surface. It is only when a player slows, that water will heap up behind them, and so push them forwards.

I would expect that water, in laminar flow on the slide surface, would be traveling slower than the player. If you sit in a kayak in the middle of a flowing river, you will see you are moving slightly faster down the river, than is the surface water.

 

[jbriggs444]

you will see you are moving slightly faster down the river, than is the surface water.

It has been my experience that objects floating in water such as sticks, leaves, canoes and inner-tubers are more heavily influenced by the wind then by a propensity to slide down the slanted water surface.

However, I have not explored the mathematics of an idealized situation corresponding to flotation down a slow-moving river. Nor the idealized situation corresponding to a lubricated human snowplow on a radically steeper slope.

For high speed, I would intuit that you are looking to hydroplane. For safety, I would intuit that you are attempting to avoid that scenario due to the positive feedback that it entails.

 

[Baluncore]

It has been my experience that objects floating in water such as sticks, leaves, canoes and inner-tubers are more heavily influenced by the wind then by a propensity to slide down the slanted water surface.

Winds are important, but when it is dead calm, a boat travels faster downstream than sticks, leaves, rafts and inner-tubers, that have lower characteristic hull speeds and a greater relative displacement in the water.

Without paddling, a kayak will gradually accelerate to a speed slightly faster than other objects on the surface, especially when pointed downstream. That statement is based on long peaceful experience and observation, not on the armchair reasoning and scientific analysis, that agrees with the observations.

The external wind vector is less important on a water slide, since the velocity of the player generates an apparent headwind, with an air resistance determined by the player's drag profile. Considering the changes in slope, I doubt the slide would last long enough to establish an equilibrium.

 

[russ_watters]

Good point. I did a Google search on Waterslide Accidents and got lots of hits. So "optimization" would seem to need some consideration of safety, not just maximum speed...

I can think of a couple of others: cost and comfort/"ride".