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  1. Clausius2

    What's the story!

    Hi everybody (to those who remember me). Hope all is well with you. I'm now in the bay area, in a city called "High Stick" in spanish and work in an office very close to the MemChu. :)
  2. Clausius2

    Experimental Fluid Mechanics Videos Series

    There you go: http://www.physorg.com/news/2012-01-wings.html I think that's a valuable resource for explaining why aircrafts fly. BTW Hello everybody! Long time no see you! I work now in the bay area in a well known university: Fear the tree! :) Hope all is well with you.
  3. Clausius2

    Experimental Fluid Mechanics Videos Series

    Ops! Obviously GI Taylor, Shercliff and Lighthill were fine british men, so not all merit goes to USA.
  4. Clausius2

    Hiked in Yellowstone, Zion, Bryce, Capitol Reef

    Just wanted to let you know, to those PF veterans that may remember me from writing here a long time ago, that, four years and a half after, I'm finally done with my phd and with my adventures in usa (for the moment)! I'll go back to europe after this (to france). I also wanted to add that...
  5. Clausius2

    Southern California is burning!

    I live in San Diego. Fortunately I didn't have to evacuate, I live near UCSD and even though the fire got very near we were lucky. All this stuff seems a cathastrophe, half of the county burnt out. I am not republican or democrat, but I honestly think that Governator's team and San Diegan...
  6. Clausius2

    Moleculer viscosity? Eddy viscosity?

    Eddie Viscosity is an imaginary concept (also termed 'The Ansatz' in turbulence). It does not exist as the molecular viscosity, which is a well defined transport coefficient as stated by the Kinetic Theory. The Eddie Viscosity hypothesis was posed for making the things simpler, in the sense that...
  7. Clausius2

    Should I pursue and Ph.D. in Aerospace Engineering or stick with a Masters Degree?

    I have over here people whose research focus involves control theory applied to trajectory stabilities, aircraft control systems and optimization. Of course that if you want to get your hands dirty you better go to look for a job. A Ph.D. gives you a couple of things: - an outstanding...
  8. Clausius2

    Feliz Cumpleaños, Clausius2!

    Thanks everyone!. The beach was crowded today!! Is there a concert of HS in LA????. Holy molly!!. I didn' now that!!. Let me see...
  9. Clausius2

    Feliz Cumpleaños, Clausius2!

    Gracias man. Lemme know if you come down to SD, you deserve a couple of beers. Right now I'm going to buy some food to grill, we are gonna do bbq on the beach today for my birthday. 1 abrazo, J.
  10. Clausius2

    Fluid Dynamic: Stokeslet? Rotlet?

    Basically yes, but only for axisymmetric shapes, like a sphere or an ellipsoid moving parallel to its major axis. It is not that the force can be viewed as a point force, the force is just a number or a vector. It is said that the flow field- caused by the motion of the body through a fluid at...
  11. Clausius2

    Fluid Dynamic: Stokeslet? Rotlet?

    I'm not gonna come out with the mathematical theory here, but you might realise by yourself that any body, no matter its shape, is viewed from far far away as a point force when moving through a viscous fluid. From your studies on PDEs and Green's Functions you should be able to understand the...
  12. Clausius2

    Fluid Dynamic: Stokeslet? Rotlet?

    I'm gonna clarify you what is a Perturbation series. Afterwards I have to go to sleep. Take Stokes scaling resultant momentum equation: Re\overline{u}\cdot \nabla\overline{u}=-\nabla P+\Delta\overline{u} This scaling is well posed if Re\ll 1. Imagine that I want to solve that equation defining...
  13. Clausius2

    Fluid Dynamic: Stokeslet? Rotlet?

    That is damn right!. You answered yourself. I happen to not remember any special chapter of a book talking about this stuff deeply. Again I would recommend you to take a look at Batchelor's book. Non dimensionalization is only made via experience and common sense. Sometimes one only needs to...
  14. Clausius2

    Fluid Dynamic: Stokeslet? Rotlet?

    Hey man, these questions that depart from typical engineering questions are more than welcome, and moreover if it is related to this stuff of neglecting things in fluid mechanics and sentences of the type "of the order of". That is what I am up to everyday on my desk. Maybe someday you'll be a...
  15. Clausius2

    Fluid Dynamic: Stokeslet? Rotlet?

    Yes, and you will, you will keep on seeing that stuff many times. That is the essence of fluid mechanics. You better understand it. Even though some people here and there claim to be engineers, I have never seen such a fantastic maneuver of practical engineering such as that proposed by former...
  16. Clausius2

    Flow rate through a squre tube

    sure you are not going to have the last word here while I'll be able to log on. Sure that using what Minger gave is a little bit out of scope for this problem. But integrating given a pressure loss, integrating the u(x,y) formulas there on a differential element of pipe section dS=dxdy gives...
  17. Clausius2

    Flow rate through a squre tube

    Now it's my turn to talk and to tell you that once again you show a narrow knowledge about the Basics. I will leave to use the calculators to the practising engineers. In the meanwhile I'll be talking about physics. Minger is right, the solution he posted is an exact solution for viscous flow...
  18. Clausius2

    Flow rate through a squre tube

    Last thing, I could't stand quiet with this. By that fred you are pre assumming already high Re. Pressure, gravitational, kinetic and no more energies right?. Sounds familiar to me when talking about high Re numbers. Where is the Viscous Dissipation \phi or also called Rayleigh Dissipation...
  19. Clausius2

    Flow rate through a squre tube

    allright. I withdraw. Seems ridiculous to me that this discussion is centered around some specific comments or words like roughness and around customer-chosen paragraphs ignoring the rest, and not paying any attention to the physical arguments I have given even for a simple estimation of Re of 1...
  20. Clausius2

    Green Function Question

    I...I don't see how can diverge. It's a multiplication of trigonometric functions isn't it?. How can that integral diverge?.
  21. Clausius2

    Flow rate through a squre tube

    And I am going to add an addendum: Even though you may have much more experience than me on all these stuffs, I think I am satisfied enough if a simple grad student 24 years old with only the experience of the books has been able to challenge your knowledge of several years in well known...
  22. Clausius2

    Flow rate through a squre tube

    Allright, thanks for not feeding the flames, sometimes I take it more seriously than what I should. Anyways I hope the reader is learning something out of all of this. At least we agree that the stuff of my link has been useful, and still it's gonna be the workhorse of my answer, since you have...
  23. Clausius2

    Flow rate through a squre tube

    Here we go, on the contrary I am not going to throw here my CV, that is probably much better than yours one 20 years ago. I will use scientific arguments instead of medals: Even though the Crane paper says that, that makes no sense sir!!!. What a naive generalization!!!. What a reduction of...
  24. Clausius2

    Flow rate through a squre tube

    The holly molly, it is impossible to deal with Q_Goest. It seems we are coming from Universes totally different, where the physics laws are completely different. I wish I could know the other Universe, if it exists. I will try to answer you rather than to answer the OP later, now I have work to...
  25. Clausius2

    Flow rate through a squre tube

    It seems that we have forgotten the lesson about viscous flows. I hope you are not planning to calculate the mass flow using the -Bernouilli Corrected equation with losses- or whatever is the name. Looking at the left hand part of the Moody chart the only thing that you find for Low Re is the...
  26. Clausius2

    Flow rate through a squre tube

    You didn't clarify anything. You don't know what intake pressure you have. Think about it a little bit more and come out with the Reynolds Number by yourself. It will give you what kind of flow best addresses your problem. I won't be helping you farther.
  27. Clausius2

    Flow rate through a squre tube

    My question is: how is it possible to push water at 1 bar being the end of the pipe open to the atmosphere (1 bar)?. In order to generate flow you need a pressure gradient. There is only one case in which you wouldn't need a pressure gradient. And that case is one that belongs only to the...
  28. Clausius2

    Bow waves and air Ripples

    The holy, Rainman, you have to tell me sometime what are you working on (if not classified). Sounds interesting. If you come down to San Diego let me know and we can have a couple of beers.
  29. Clausius2

    Chemistry Using gas law to find moles of SO3 formed

    Allright, don't try something called Chemical Equilibrium. Try something called Follow What Gokul Pointed Out. :biggrin:
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