mechanical

From Dr. Russell Qualls, BAE [129.101.65.192] - 10/27/06 5:57 PM

As you know, this is such an important project.  Nice work, everyone.  I especially liked your presentation in the mechanical testing page-the graphics are nicely done, the page is well laid out and thorough.  On the development of your equations to apply Darcy's law to your filter, the head in the equation for flow through the bottom of the filter should also include the thickness of the filter.  That is, total head on upper surface of filter is h=H+b, and total head on underside of the filter (exposed to atmospheric pressure) is 0 if we take the datum as coincident with the underside of the filter.  Therefore, the change in head between the two sides of the filter is H+b-0 or just H+b.  I haven't worked through the integration, and it may not change your solution much, especially when the head is large, but as the depth above the filter gets small, it will maintain a higher rate of flow through the filter, because dh/dz will approach b as h->0 instead of dh/dz approaching zero.  This will reduce the total time it takes to filter the full container of water (but you will have to resolve the equations to determine whether it makes a measurable difference in the time).  Anyway, this is a small adjustment.  I like what I see so far.  Keep up the good work.

From Dr. Sunil N. Patankar [129.101.98.164] - 10/27/06 7:59 AM

I had the pleasure of visiting your website. It is very impressive. Your team is working on a great cause and there is a lot for the world to learn from your efforts.

 Dr. Sunil N. Patankar

University of Idaho

(pata1630@uidaho.edu)