Comments for Models, Methods, Software http://danhughes.auditblogs.com The purpose of computing is insight, not numbers. Hamming Mon, 12 May 2008 11:07:21 +0000 http://wordpress.org/?v=2.3.1 Comment on Mass and Energy Conservation by Dmitri http://danhughes.auditblogs.com/2007/08/30/mass-and-energy-conservation/#comment-729 Dmitri Wed, 16 Apr 2008 17:38:45 +0000 http://danhughes.auditblogs.com/2007/08/30/mass-and-energy-conservation/#comment-729 Personalyl I agree with renewable energy. Too much is being placed on conserving and not finding a solution. Personalyl I agree with renewable energy. Too much is being placed on conserving and not finding a solution.

]]> Comment on Chaos and ODEs Part 1d: Calculations and Results by Tom Vonk http://danhughes.auditblogs.com/2007/11/20/chaos-and-odes-part-1d-calculations-and-results/#comment-721 Tom Vonk Wed, 09 Apr 2008 13:06:18 +0000 http://danhughes.auditblogs.com/2007/11/20/chaos-and-odes-part-1d-calculations-and-results/#comment-721 Alexi Thekasski I am aware of Kolmogorov work as well as of the Ruelle&Takkens "clarification" that you linked . I am also aware that the Ruelle&Takkens result doesn't apply to a general case even if it is far from being "skinny" . As for "strange" attractors - it is only a word , they have indeed nothing strange like quark "colors" are not really colors . I do not know the russian papers from the 60ies as we are in the meantime 50 years later but if there are some new russian results that go beyond the 60ies "failures" and are available , links would be of course welcome . Alexi Thekasski

I am aware of Kolmogorov work as well as of the Ruelle&Takkens “clarification” that you linked .
I am also aware that the Ruelle&Takkens result doesn’t apply to a general case even if it is far from being “skinny” .
As for “strange” attractors - it is only a word , they have indeed nothing strange like quark “colors” are not really colors .

I do not know the russian papers from the 60ies as we are in the meantime 50 years later but if there are some new russian results that go beyond the 60ies “failures” and are available , links would be of course welcome .

]]> Comment on Chaos and ODEs Part 1d: Calculations and Results by Alexi Tekhasski http://danhughes.auditblogs.com/2007/11/20/chaos-and-odes-part-1d-calculations-and-results/#comment-720 Alexi Tekhasski Tue, 08 Apr 2008 04:53:36 +0000 http://danhughes.auditblogs.com/2007/11/20/chaos-and-odes-part-1d-calculations-and-results/#comment-720 Tom Vonk, Regarding results of Ruelle and Takens, you may want to read their clarification, http://projecteuclid.org/DPubS/Repository/1.0/Disseminate?view=body&id=pdf_1&handle=euclid.cmp/1103857674 As V.I.Arnold said somewhere, the Ruelle-Takens construction occupies a "skinny" set of measure near zero in the space of dynamical systems spanned from N-S equations. Actually, the studies of turbulence in early 1960's have been conducted at a group of mathematicians lead by Kolmogorov at Moscow University; they discovered a link of N-S equations with more generic "hyperbolical" systems. The problem appeared to be of tremendous complexity, no clean results were obtainable, so the honest scientist decided not to make a big deal of their "unsuccessful" efforts. Later some of their results were re-discovered by West, and widely publicized. As another physicist from Siberia, B.V. Chirikov used to mention in his lectures about dynamical systems, "strange attractors are strange only to strangers". Cheers, - Alexi Tom Vonk,
Regarding results of Ruelle and Takens, you may want to read their clarification,
http://projecteuclid.org/DPubS/Repository/1.0/Disseminate?view=body&id=pdf_1&handle=euclid.cmp/1103857674
As V.I.Arnold said somewhere, the Ruelle-Takens construction occupies a “skinny” set of measure near zero in the space of dynamical systems spanned from N-S equations. Actually, the studies of turbulence in early 1960’s have been conducted at a group of mathematicians lead by Kolmogorov at Moscow University; they discovered a link of N-S equations with more generic “hyperbolical” systems. The problem appeared to be of tremendous complexity, no clean results were obtainable, so the honest scientist decided not to make a big deal of their “unsuccessful” efforts. Later some of their results were re-discovered by West, and widely publicized. As another physicist from Siberia, B.V. Chirikov used to mention in his lectures about dynamical systems, “strange attractors are strange only to strangers”.
Cheers,
- Alexi

]]> Comment on Mass and Energy Conservation by Renewable Energy http://danhughes.auditblogs.com/2007/08/30/mass-and-energy-conservation/#comment-693 Renewable Energy Sun, 16 Mar 2008 13:50:31 +0000 http://danhughes.auditblogs.com/2007/08/30/mass-and-energy-conservation/#comment-693 For me it doesnt matter if we are using models or not to analyze and predict the future of our energy. What matters most is our discipline and dedication to help in our very own little ways to conserve energy for the future. We should invest more money on the research in the actual preservation and conservation of energy. For me it doesnt matter if we are using models or not to analyze and predict the future of our energy. What matters most is our discipline and dedication to help in our very own little ways to conserve energy for the future.

We should invest more money on the research in the actual preservation and conservation of energy.

]]> Comment on Dissipation of Fluid Motions into Thermal Energy by Dan Hughes http://danhughes.auditblogs.com/2007/06/03/dissipation-of-fluid-motions-into-thermal-energy/#comment-692 Dan Hughes Sat, 15 Mar 2008 22:35:12 +0000 http://danhughes.auditblogs.com/2007/06/03/dissipation-of-fluid-motions-into-thermal-energy/#comment-692 MDA, the factor of 3 is to account for the efficiency (more correctly, the inefficiency) of the energy-conversion processes. It does not, and actually cannot, change the units. It's a rough average value. Maybe I don't understand your comment? MDA, the factor of 3 is to account for the efficiency (more correctly, the inefficiency) of the energy-conversion processes. It does not, and actually cannot, change the units. It’s a rough average value. Maybe I don’t understand your comment?

]]> Comment on Dissipation of Fluid Motions into Thermal Energy by MDA http://danhughes.auditblogs.com/2007/06/03/dissipation-of-fluid-motions-into-thermal-energy/#comment-691 MDA Sat, 15 Mar 2008 22:04:08 +0000 http://danhughes.auditblogs.com/2007/06/03/dissipation-of-fluid-motions-into-thermal-energy/#comment-691 "Worldwide energy consumption by the human race is over 446 Quadrillion BTUs at the present time. This is equivalent to 131,400 TWhr or 471,000 PJ (= 10^15 J) per year. If we take an average efficiency to be 33%, the total energy conversion is about 3 times the consumption, or 1,413,000 PJ per year = 1.413 x 10^21 J/year." The 446 quads are already in units of heat, so there is no need to multiply by three. “Worldwide energy consumption by the human race is over 446 Quadrillion BTUs at the present time. This is equivalent to 131,400 TWhr or 471,000 PJ (= 10^15 J) per year. If we take an average efficiency to be 33%, the total energy conversion is about 3 times the consumption, or 1,413,000 PJ per year = 1.413 x 10^21 J/year.”

The 446 quads are already in units of heat, so there is no need to multiply by three.

]]> Comment on Why are Multiphase/Multifield/Multifulid Fluid Flow Models Ill-Posed? by Dan Hughes http://danhughes.auditblogs.com/2007/12/08/why-are-multiphasemultifieldmultifulid-fluid-flow-models-ill-posed/#comment-690 Dan Hughes Sat, 15 Mar 2008 12:21:29 +0000 http://danhughes.auditblogs.com/2007/12/08/why-are-multiphasemultifieldmultifulid-fluid-flow-models-ill-posed/#comment-690 The usual approach that is used to resolve one of the the problems that arise in the situations that are the subject of this post is employed in <a href="http://hps.elte.hu/zagoni/idojaras2004_Vol108_No4.pdf" rel="nofollow">Miskolczi 2004</a> and <a href="http://met.hu/doc/idojaras/vol111001_01.pdf" rel="nofollow">Miskolczi 2007</a>. The usual approach that is used to resolve one of the the problems that arise in the situations that are the subject of this post is employed in Miskolczi 2004 and Miskolczi 2007.

]]> Comment on Radiative-Equilibrium Models and the Weather Temperature by Tom Vonk http://danhughes.auditblogs.com/2008/02/11/radiative-equilibrium-models-and-the-weather-temperature/#comment-682 Tom Vonk Fri, 07 Mar 2008 15:37:16 +0000 http://danhughes.auditblogs.com/2008/02/11/radiative-equilibrium-models-and-the-weather-temperature/#comment-682 Btw while we are at the subject of freedom degrees . I don't know if some of you did some linear programming . I did a lot of that many years ago and there are really strange things happening when one goes down from an undetermined system and begins to impose more and more constraints (= suppressing freedom degrees) . That teaches among other an extreme distrust to additionnals degrees of freedom unless one has a very good (aka physicaly justified) reason for it . Btw while we are at the subject of freedom degrees .
I don’t know if some of you did some linear programming .
I did a lot of that many years ago and there are really strange things happening when one goes down from an undetermined system and begins to impose more and more constraints (= suppressing freedom degrees) .
That teaches among other an extreme distrust to additionnals degrees of freedom unless one has a very good (aka physicaly justified) reason for it .

]]> Comment on Radiative-Equilibrium Models and the Weather Temperature by Tom Vonk http://danhughes.auditblogs.com/2008/02/11/radiative-equilibrium-models-and-the-weather-temperature/#comment-681 Tom Vonk Fri, 07 Mar 2008 15:30:10 +0000 http://danhughes.auditblogs.com/2008/02/11/radiative-equilibrium-models-and-the-weather-temperature/#comment-681 I didn't know that the blog didn't accept the brackets . The last phrase above should read : [ViVj]is for me definitely the latter . I didn’t know that the blog didn’t accept the brackets . The last phrase above should read : [ViVj]is for me definitely the latter .

]]> Comment on Radiative-Equilibrium Models and the Weather Temperature by Tom Vonk http://danhughes.auditblogs.com/2008/02/11/radiative-equilibrium-models-and-the-weather-temperature/#comment-680 Tom Vonk Fri, 07 Mar 2008 15:26:16 +0000 http://danhughes.auditblogs.com/2008/02/11/radiative-equilibrium-models-and-the-weather-temperature/#comment-680 Dan You might consider reading : http://met.hu/doc/idojaras/vol111001_01.pdf I have read it only once so have no precise opinion sofar . But the model looks very easy to implement (well there is that LBL bit that could complicate) and interesting enough to look at it . Lucia Increasing the freedom degrees of a system is a 2 edged sword . Either they may correspond to something and lead to farther insights or they may correspond to nothing and lead to confusion . So there is no absolute answer for all cases - very simple can be too simple and it gains with additionnal degrees while very complex can be too complex and it becomes unphysical with additionnal degrees . is for me definitely the latter . Dan

You might consider reading : http://met.hu/doc/idojaras/vol111001_01.pdf
I have read it only once so have no precise opinion sofar .
But the model looks very easy to implement (well there is that LBL bit that could complicate) and interesting enough to look at it .

Lucia

Increasing the freedom degrees of a system is a 2 edged sword .
Either they may correspond to something and lead to farther insights or they may correspond to nothing and lead to confusion .
So there is no absolute answer for all cases - very simple can be too simple and it gains with additionnal degrees while very complex can be too complex and it becomes unphysical with additionnal degrees .
is for me definitely the latter .

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