This is a request for a way for me to avoid using CFD - I've done my background survey and I see that using CFD is non-trivial <grin>. What I want , however, I feel must be a standard solution which is well known to CFD practitioners - but I've spent hours Googling for it and can't find it . Can SKS point me in the right direction please? I would like to have a mental picture of the flow of air from a room ( let's assume it's an infinitely big room) around and into the entrance to a cylindrical dust extractor pipe - the sort you would use as a serious hobbyist woodworker to extract dusty air from a woodturning lathe. Let's say the pipe diameter is 6 inches ( 150 mm ) and that the average air speed in the cylindrical duct is about 4000 feet per minute ( about 70 feet per sec or 20 metres per sec ). Ideally I'd like to be able to find online pictures of the flow patterns and also approximate indications of the actual air speeds around the entrance to the duct , for distances of the order of up to a few duct diameters from the inlet. I'd be very grateful for any pointers. Robert

Try ASHRAE Handbook -Systems - volume - available in any good engineering library.

Look under "Air flow" - "Local exhaust systems"

ASHRAE = American Society of Refigeration and Air Conditioning Engineers

There are also some library books with "Industrial Ventilation" ...?? "and Safety" in the title that will have some of the figures you want

Search Amazon.com using "industrial ventilation" Got three good hits - the ones at the start of the list. An good library should have some of them.

Thanks to amorriison for the suggestions - it would be nice to have access to a good library or an engineering library <grin>. Risking sounding wimpish , is there anything online that might help? Robert

Try

http://www.vtt.fi/aut/safety/tutkryh...ilm/aaberg.pdf

http://www.airflow.ethz.ch/projects/...tion_paper.htm

http://www.louisville.edu/admin/dehs/lsfume.htm

http://www.osha-slc.gov/dts/osta/otm...otm_iii_3.html

Good stuff here: http://www.osha.gov/SLTC/silicacryst...chapter_3.html

http://www.osha.gov/pls/oshaweb/owas...ch_str=airflow

http://www.epa.gov/labs21century/con...ons/varley.pdf

http://www.collegedalecasework.com/PDF/sefa1_3.pdf

http://www.dec.state.ny.us/website/ppu/ecppwood.pdf

http://www.nmenv.state.nm.us/Green_Z...ing_packet.pdf

I've tried the links that amorriison has suggested trying (in the previous in this thread): not one had previously come up in my Googling <sigh>. To help resolve my original query , these links are indeed handy ( best highest up the list )and are worth trying by anyone else following a thought through route to cleaner air in the woodworking shop. Many thanks to amorriison. Best wishes, Robert Hillier