Recent content by sams_rhythm

I found these notes on classical dynamics really clear, particularly page 24: http://www.damtp.cam.ac.uk/user/tong/dynamics/clas.pdf I find this really cool.

What is a PSD? The power spectral density, I guess.

cjl, it depends what the experiment is trying to show. It certainly shows that the flow through an IV can in some situations be increased if you add more bags, as long as the pressure drop from each bag is mainly upstream of the junction. It also shows that the pressure drop downstream of the...

The narrowest part of the line will lead to the biggest pressure loss. If you look at the expression for pressure drop here http://en.m.wikipedia.org/wiki/Hagen–Poiseuille_equation it scales like r^-4 so width often has a very dominant effect. For the reasons you mention, I suppose (guessing...

Sorry. Didn'y mean to annoy you. I thought you were interested. Apologies for any offence caused.

It's buoyancy of the ball acting upwards isn't it. Think "Archimedes principle". Viscosity makes no difference naicidrac. You have to have motion for that to make a difference, not a static situation.

Drakkith, I think it is related very much to what you say. In your example everything is static so it happens just like you say. Once the fluid starts to flow, then there will be pressure loss due to friction at the wall and the pressure downstream will be less than 100 pounds. I guess for the...

Aha. Now I understand you experiment better. What's wrong with my experiment? I think it is a good demonstration of P = \rho g h rather than P = m g / A There is one thing that stops either of our experiments being analogous to an IV. In an IV there will be the largest pressure loss in the...

We are testing two hypotheses. Hypothesis 1: Pressure = mass * gravity / Area In the sink and the bath, the plug holes are exactly the same area. Gravity is the same. The mass of water in a bath is larger. this would suggest that pressure at the plug hole in the bath is greater than the...

Andy, I did your experiment as I explained with the bath and sink comparison. Why don't you do that one and explain it with your theory. If you'd like a reference on this try looking up hydrostatics on Wikipedia or a textbook. Fluid mechanics by Kundu is a masters level text, but a high...

Biebs, did you find out anything more about this? Do you think using two bags might have led to fluid flowing from one bag to the other? Did wikipedia make any sense? I think the way that flow is increased in an IV is by using a wider diameter catheter. In fact, I thought they use a wider...

Andy, no, I disagree. If I fill a sink with 10 cm depth of water or a bath with 10 cm depth of water, the sink empties quicker. This is essentially the same as your experiment. I'd need to know more about whether friction from the walls of your funnels was playing a role to try and understand...

I have to say I'm with cjl not Andy. I don't know if this will work, but here goes. l l l l l l l l l l l l l l l l l l l l l l_____l l l__________________________l Doh. I...