rwjefferson Posted July 30, 2013 Share Posted July 30, 2013 (edited) welcome to my wormhole.iii def: topspin the side rolling into the relative headwind! newton.001 def: n a measure of force and mass acceleration syns: i and m and a and g bernoulli.007 fluent flowing faster over a horizon means lower pressure and vice versa Airmass streams downwards behind slippery shiny topspinning bowling balls. Does lower pressure over accelerate fluent airmass downwards? newton.102 fluent airmass departing upwards forces spinning ball mass down Topspinning stitches and dimples drag airmass around and under and upwards. Do satin surfaced underspinning ping~pong balls demonstrate lift? inertial pressure differential.001 newton in~verse bernoulli As inertial and pressure differential are relatively equivalent and streamlines depart straight and level. How much grit must be glued around a slippery shiny topspinning ball before airmass departs straight and level; no matter spin? navier stokes.001 [math]\rho \left( \frac{\partial \mathbf{v}}{\partial t} + \mathbf{v} \cdot \nabla \mathbf{v} \right) = - \nabla p + \nabla \mathbf{T} + \mathbf{b}[/math] navier stokes.101 The stress terms p and [math]\scriptstyle \boldsymbol{\mathsf{T}}[/math] are yet unknown, so the general form of the equations of motion is not usable to solve problems. Besides the equations of motion—Newton's second law—a force model is needed relating the stresses to the fluid motion. What do the stress terms p and [math]\scriptstyle \boldsymbol{\mathsf{T}}[/math] mean to you? Can you prove it? Really? ItS peace ron when the legend tells better tell the legend Edited July 30, 2013 by swansont fix math tags Link to comment Share on other sites More sharing options...
imatfaal Posted July 30, 2013 Share Posted July 30, 2013 ! Moderator Note Moved to speculations - mainly because it is so difficult to know what the point of debate is actually meant to be. Link to comment Share on other sites More sharing options...
swansont Posted July 30, 2013 Share Posted July 30, 2013 ! Moderator Note And if this is another example of asking a question so you then then pontificate, it will be locked. You have been warned about this. 2 Link to comment Share on other sites More sharing options...
studiot Posted July 30, 2013 Share Posted July 30, 2013 (edited) If you are going to invoke the Navier Stokes equations, please note they are plural. The other half of the pair to the version you have quoted is [math]\nabla .v = 0[/math] Please also note that the one you have used is for incompressible flow. However the other material in your post suggests you are continuing your investigation of airborne phenomena. You should therefore ensure that incompressible conditions apply in any such use of these NS equations, which sometimes happens in airflow, but not always. As to the apparent specific question The p terms refer to normal stresses, the T terms to tangential (shear) stresses. Edited July 30, 2013 by studiot Link to comment Share on other sites More sharing options...
Bignose Posted July 30, 2013 Share Posted July 30, 2013 (edited) The p terms refer to normal stresses, the T terms to tangential (shear) stresses. Right, and we propose constitutive models for the shear stress (often invoking Newton's viscosity as one example). The set of equations solve for the velocity field and pressure. rwjefferson, I would entreat you to please read any of the many, many books about fluid mechanics. These are basic questions that are typically answered in the first chapter or two. If you would like recommendations, I would be happy to give you some. But, I, like swansont, am afraid that this thread will be your typical ask 12 random questions and then a 'gotcha!' when you think you've won a point. I don't mind helping share knowledge on a subject I really enjoy -- fluid mechanics. But I'm not here to play games. Do satin surfaced underspinning ping~pong balls demonstrate lift? Yes. This happens almost anywhere there is a physical boundary. Quite simply, the solid structure of the ball can support shear stresses whereas the fluid does not. Edited July 30, 2013 by Bignose Link to comment Share on other sites More sharing options...
studiot Posted July 30, 2013 Share Posted July 30, 2013 (edited) Quite simply, the solid structure of the ball can support shear stresses whereas the fluid does not. Many folks misinterpret this statement and imagine it means that there is no shear stress in a fluid. This is far from the case. A solid can 'support' shear stresses without deformation, in which case it is totally rigid. Or it deflects a certain amount, but no more, under a given shear stress, in which case one of the responses -elastic, or some other applies. On the other hand The shear stress in a fluid at rest is zero. But the response of a fluid to imposed shear stress is movement. A fluid in motion suffers shear stress. Edited July 30, 2013 by studiot Link to comment Share on other sites More sharing options...
Bignose Posted July 30, 2013 Share Posted July 30, 2013 Many folks misinterpret this statement and imagine it means that there is no shear stress in a fluid. Good point. In short, I think it best to reiterate that the OP would be well advised to consult an introduction to fluid mechanics book. It is a subject with an extensive literature. Link to comment Share on other sites More sharing options...
rwjefferson Posted August 8, 2013 Author Share Posted August 8, 2013 Are normal and shear stresses more likely a function of inertial pressure differential or curvature or something different? And what does the state of matter have to do with it? really peace ron Link to comment Share on other sites More sharing options...
Bignose Posted August 8, 2013 Share Posted August 8, 2013 Are normal and shear stresses more likely a function of inertial pressure differential or curvature or something different? And what does the state of matter have to do with it? really The 'pressure differential' is the grad p term. And the shear stresses are in the grad T term. Mathematically, you can add the two terms together, and call it something like a 'total stress'. But the equation shows how the two are related to one another. Example #1: a cylindrical pipe with high pressure at one end and low pressure at the other. The shear stresses form because of the pressure drop. Example #2: two infinite parallel planes have a fluid between them. The 1st plane is held steady, but the second moves at a constant velocity. In this case, the moving surface forms the shear stress, and a pressure differential forms because of the shear. So, neither is really a 'function' of the either. They are just related by the N-S equations. And the state of the matter depends on what constitutive equations you use for the shear stress. A Newtonian fluid has different constitutive equations than a non-Newtonian pseudo-plastic. And a solid doesn't obey the N-S eqns. They have a similar conservation of momentum equation, but it isn't the same. Link to comment Share on other sites More sharing options...
rwjefferson Posted August 13, 2013 Author Share Posted August 13, 2013 standing against trolls~20.13.08.12,08;141 def: pi what's force got to do width it.viii def: current wiki yesterday's best understanding Del, or nabla, is an operator used in mathematics, in particular, in vector calculus, as a vector differential operator, usually represented by the nabla symbol. When applied to a function defined on a one-dimensional domain, it denotes its standard derivative as defined in calculus. When applied to a field (a function defined on a multi-dimensional domain), del may denote the gradient (locally steepest slope) of a scalar field (or sometimes of a vector field, as in the Navier–Stokes equations), the divergence of a vector field, or the curl (rotation) of a vector field, depending on the way it is applied. Is total stress (by any other Name) a function of initial inertial differential or bang~entropy or curvature or something even more magical than existence? thanks ron as horizon lowers pressure declines over time Link to comment Share on other sites More sharing options...
Bignose Posted August 13, 2013 Share Posted August 13, 2013 Is total stress (by any other Name) a function of initial inertial differential or bang~entropy or curvature or something even more magical than Where do you get any of that from?!? I tried to tell you above that I wasn't going to play games like this, where you take things out of context or try a gotcha. Total stress is just the sum of the grad p and the grad T terms. Link to comment Share on other sites More sharing options...
rwjefferson Posted August 20, 2013 Author Share Posted August 20, 2013 its a curse of course.iIi def: r~bvious not from what authority tells you so syn: those that fear truth blame context or messenger Is gravity a state of force or a relatively equivalent mathematical construct? Will maths experts ever admit alphanumeric models and other images sometimes deceive? When will a maths expert calculate the drag of weakly interactive particles gravitating toward mass? Do maths experts know how to put a genie back into the bottle? Is gravity a state of force or an alphanumeric construct? def: dogma what authority tells you so r -2 Link to comment Share on other sites More sharing options...
Bignose Posted August 20, 2013 Share Posted August 20, 2013 Is gravity a state of force or a relatively equivalent mathematical construct? Will maths experts ever admit alphanumeric models and other images sometimes deceive? When will a maths expert calculate the drag of weakly interactive particles gravitating toward mass? Do maths experts know how to put a genie back into the bottle? What does any of this have to do with the N-S equations? Link to comment Share on other sites More sharing options...
Unity+ Posted August 20, 2013 Share Posted August 20, 2013 To be honest, I can't tell if I can't read his sentences correctly or if they are actually just gibberish. standing against trolls~20.13.08.12,08;141 As if this has any relevance to the discussion. Link to comment Share on other sites More sharing options...
swansont Posted August 20, 2013 Share Posted August 20, 2013 its a curse of course.iIi def: r~bvious not from what authority tells you so syn: those that fear truth blame context or messenger Is gravity a state of force or a relatively equivalent mathematical construct? Will maths experts ever admit alphanumeric models and other images sometimes deceive? When will a maths expert calculate the drag of weakly interactive particles gravitating toward mass? Do maths experts know how to put a genie back into the bottle? Is gravity a state of force or an alphanumeric construct? def: dogma what authority tells you so r ! Moderator Note This is off topic, and also personal commentary about another poster, both of which are against the rules. Link to comment Share on other sites More sharing options...
rwjefferson Posted September 1, 2013 Author Share Posted September 1, 2013 What might stress terms like p and T really mean? stress tensor.001 Are stress and pressure and tension states of force? Are stress terms like p and T alphanumeric symbols and grads or fields or curvature? Or might stress terms like p and T also mean functions and derivatives of pressure and tension? welcome to my wormhole.007 def: byLaw whereas 'that is the most ridiculous nonsense ever posted' is construed not an ad hominem attack or personal commentary bad dogma.101 My goal is to contribute to science and evolution. That the (un?)intended consequence of your game is to thwart and obfuscate and hijack is not necessarily the simple truth you should so readily reveal. Does the relatively rough surface of topspinning balls accelerate air mass around and under and upwards? Does airmass forced around and over and downwards drag and lift underspinning ballmass back and up? If you so fear to admit basic truth, just turn away and hold your peace and let me speak mine own. peace ron those that fear truth condemn the messenger Link to comment Share on other sites More sharing options...
Bignose Posted September 2, 2013 Share Posted September 2, 2013 (edited) If you so fear to admit basic truth, just turn away and hold your peace and let me speak mine own. I have no fear to admit the basic truth that you really ought to go and read an introduction to fluid mechanics book. Because if you really wanted the answers to these questions, they are discussed in many numerous texts. It is also a basic truth that I am very, very hesitant to answer because I think there is an extraordinary chance you'll just use the words out of context or deliberately misunderstand in order to fit your personal agenda. Again, please go and read an introductory fluid mechanics text. If you want recommendations, I will provide that, and if you have questions from the text, I'll answer those. You have had over a month since this thread was started; you can find many cheap fluid mechanics books on used book websites; you really don't have much of an excuse not to have looked over a basic fluid mechanics text by now, if and only if you really sought answers to these questions. I suspect that you are playing games, again, though. Edited September 2, 2013 by Bignose Link to comment Share on other sites More sharing options...
rwjefferson Posted September 6, 2013 Author Share Posted September 6, 2013 Are stress terms like p and T functions of pressure and tension? newton.001 mass in motion means constant vector and velocity unless forced your nose grows every time you post.viii truth is out of context only under the cloak of dogma Cite the Book and Chapter and Verse that proves curvature is more than a reaction to force. hypervalent_ion: In some forums it is considered polite to answer the OP's questions. Are alphanumeric terms like stress and p and T functions of force? Cite the context of your answer if you so fear universal truth. peace ron a good teacher learns from all students Link to comment Share on other sites More sharing options...
Bignose Posted September 7, 2013 Share Posted September 7, 2013 whatever dude. http://www.abebooks.com/servlet/BookDetailsPL?bi=10716162191&searchurl=kn%3Dintroduction%2Bfluid%2Bmechanics%26amp%3Bsts%3Dt Link to comment Share on other sites More sharing options...
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