User talk:Giuliopp

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Wow, nobody's welcomed you yet? Welcome to Wikipedia! Kla'quot 09:32, 29 January 2007 (UTC)


Welcome!

Hello, Giuliopp, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or place {{helpme}} on your talk page and ask your question there. Again, welcome!  Kla'quot 09:32, 29 January 2007 (UTC)

Hi! In February and March 2007 you added some text to the article "Static pressure". I think this article is significantly in error, and has been since long before you made your additions. I have made my comments in the Discussion page. I am willing to re-work the article so I would be very glad if you look at the Discussion page and add your comments. Best regards.
Dolphin51 08:28, 1 December 2007 (UTC)

Hi again Giuliopp. Thanks for your patience. I have assembled my response to your comprehensive contribution on the subject of static pressure, and posted it on the Static pressure talk page. Best regards. Dolphin51 (talk) 05:06, 7 December 2007 (UTC)

Hi Giuliopp. I have posted again on the Static pressure Discussion page. Dolphin51 (talk) 03:18, 10 December 2007 (UTC)

Giulopp: Glad you seem to like the Gman tag I gave you. If you could bring a flow to stagnation isentropically in tube with a denser liquid (i.e. water or mercury) and the other ed of the tube normal to the streamline. You of course would have the normal u-curve in it. What would the difference in column heights represent. Wouldn't that be the something close to the dynamic pressure?Mangogirl2 (talk) 03:03, 27 January 2008 (UTC)

If Bernoulli is applicable, that difference in column heights indeed represents the dynamic pressure (at the point where the static port is), but the experiment proves precisely the point: the only way to determine (not measure) the dynamic pressure is by taking the difference between two measurable pressures, i.e. the fluid pressure (aka static pressure) somewhere along the streamline and the fluid pressure at a stagnation point (aka stagnation pressure). There is no way you can measure the dynamic pressure directly, taking a single pressure measurement, simply because manometers measure the force exerted by the fluid onto the area of the orifice, and the dynamic pressure is not defined as the force somewhere in the fluid divided by the area subject to it, but as the product of fluid density and square of velocity. In this sense dynamic pressure is not "real".
To say e.g. that the characteristic U-curve is due to the dynamic pressure 'entering one end and not the other' is way too simplistic to me, bordering misleading. A correct description would be for example that at the stagnation point the fluid velocity reduces to zero, therefore the kinetic energy of the fluid turns into internal energy, which implies an increase in pressure (and temperature, although noticeable only in compressible flows).
Giuliopp (talk) 02:17, 29 January 2008 (UTC)

Your point is too subtle for me. That difference in column height seems like a measurement to me. In fact I have used this technique for flow mapping in wind tunnels and around vehicles. I do not use just to determine the total speed of the vehicle as have some of your earlier comments about pitot-static tubes have implied.Mangogirl2 (talk) 01:47, 5 March 2008 (UTC)

Giuliopp: Sorry I torqued you off. I had more than one family member under my user name and decided to split myself off to a new name (while working on the trajectory optimization page. I cannot see how changing names during a typo session is a problem. The comment on the static pressue page was a silly impulse on my part but since it seemed already decided I thought it would be harmless. Obviously it bothered you and I apologize for that. Skimaniac (talk) 04:23, 13 March 2008 (UTC)

Giuliopp: In the reply to me above I cannot find where I said the dynamic pressure entered one end of the tube. I believe I said the ram air enters one end of the tube. Please don't say the flow does not enter the tube because it is stagnated. There are streamlines in and out of the tube.--skimaniac

That was just an example (I put e.g.) of a common way to describe the pitot tube, although if you replace "dynamic pressure enters" with "ram air enters", I don't see that much difference, after all.
I really don't get what you mean with streamlines being "in and out of the tube"; if we agree that the air inside the tube is stagnated, then stagnating air and streamline are mutually exclusive concepts. A streamline is by def. tangent in every point to the fluid velocity; if the velocity is zero everywhere, how can you define any streamlines? Do you mean that a streamline (or, better, fluid particle) gets just past the orifice, does a sort of U-turn and exits the tube from the same orifice? Well, to me that is a very localized effect and I can't see how it could alter the substance of the experiment, i.e. a Pitot tube creates a stagnation point at the orifice; a fluid particle arrives at the stagnation point, stops and then re-accelerate flowing along the external surface of the tube. To that fluid particle, whether the tube is solid or hollow and connected to a manometer, it doesn't matter at all (and the pressure at the stagnation point would be the same as well).
Giuliopp (talk) 23:58, 15 March 2008 (UTC)


I've closed the report at WP:SSP, as they've updated User:Skimaniac to reflect the fact that their former account was at Mangogirl2 - I'll open dialogue with them to sort out redirecting the user page and user talk page of Mangogirl2 if they're no longer going to be using it. Thanks. GBT/C 13:34, 19 March 2008 (UTC)

[edit] Request for help from Skimaniac

Giulio: I was hoping that you living in the EU you could help me out on something. I cannot remember the correct spelling for the French helo company Aerospatlie (doesn't look right to me either). If you could go the Grand Prairie, Texas page and fix the reference to that company. I would be most appreciative. Skimaniac (talk) 02:37, 22 March 2008 (UTC)

I'll leave it to you to update Grand Prairie, since you know better about that place. Anyway, the French company was Aérospatiale, although in 1992 their helicopter division was merged into Eurocopter.
Giuliopp (talk) 15:09, 22 March 2008 (UTC)