Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: newrobert on 29/11/2014 10:26:22

Title: How to measure force of moving/flowing water in a small canal
Post by: newrobert on 29/11/2014 10:26:22
I need help here.

I am working on some amusement park project where a lot of water is involved i.e. coming down from slides and then we have to lift it above 100 feet height for some other boating and amusement rides, etc.

Anyhow we have main pool on ground where all water is collected. Like 50x50x10 feet = 25,00 square feet. Around 20,000 gallon per minute is coming into this pool and then flowing out via small canals. So when amusement park is working then this is continuous cycle i.e. 20,000 gallon per minute water coming in central pool and 20,000 gallon per minute is flowing outside pool by small canals.

Small canal measurement
Canal length = 20 feet
Canal width = 5 feet
Canal height = 5 feet

Water speed: no idea yet as constant amount of water is coming in main pool and then exiting.

I want to measure what will be force of flowing water in this canal i.e. how much kinetic energy or force flowing water will create? We need more force or kinetic energy and if required we can change canal specs or even can make like slob.

What is equation/formula to measure this?

Title: Re: How to measure force of moving/flowing water in a small canal
Post by: CliffordK on 29/11/2014 21:50:43
River flow is often calculated in volume per time, for example gallons per minute.  It should be easy enough to calculate as water going into and out of the pool.  However, that doesn't give a good description of power.

Power is a function of drop.  So, if your canal has 10 feet of drop, then you would calculate the volume (mass) of water traversing the drop (distance) over unit time.

The drop will also be related to the velocity of the water.  If you poor too much water into one end of the tank before the water can exit, then it will get deeper at that point. 

I suppose you also get kinetic energy as you mentioned, so merely flowing water will have some kinetic energy (momentum) associated with it.  You might be able to augment your pumping slightly by utilizing the direction of flow, but it will be a minor constituent.  You may not wish to simply dam up the water to slow down or stop the upstream flow as you want running water.
Title: Re: How to measure force of moving/flowing water in a small canal
Post by: jeffreyH on 29/11/2014 22:42:54
You need the channel cross sectional area to start with. In rivers usually flow meters record the amount of flow but often it is calculated from other parameters without a flow meter being present. If you can calculate the flow rate through the cross section then you can derive the volume of flow past that point in a set time. The force calculation is then trivial.