@make(report) @device(lpt) @STYLE(PAPERWIDTH=33CM,LINEWIDTH=31CM,PAPERLENGTH=36CM,INDENTATION=10) @begin(titlepage) Advanced Technology Research Center | Siengg Division | Samani International Enterprises A New Correlation of the Universal Logarithmic Turbulent Fluid Velocity Distribution VASOS-PETER JOHN PANAGIOTOPOULOS II [President, Samani International Enterprises] @value(date) @begin(researchcredit) @center[@b(ABSTRACT)] The correlations of Prandtl and Deissler, as they appear, modified, in a recent textbook, are recorrelated as a single continuous function. This was originally developed while trying to determine dimensional variables which involved graphical iteration and complex calculations. With this method numerical analysis can simplify calculations on a simple programmable calulator. @end(researchcredit) @end(titlepage) @pageheading(left "Logarithmic Turbulence Correlation",center"@value(page)", right"Vasos-Peter John Panagiotopoulos II") @pagefooting(left"@value(sectiontitle)", CENTER "@value(date)", RIGHT "Samani Siengg ATRC") @chapter(Previous Work) The logarithmic correlation was initially proposed by Prandtl in 1933@foot{Prandtl, L, @i, @b<77>:105(1933).} Deissler had determined an experimental velocity distribution @foot{ Deissler, R.G., "Analysis of Turbulent Heat Transfer, Mass Transfer, and Friction in Smooth Tubes at High Prandtl and Schmidt Numbers", @i 1210, (1955), p.3.} Based on data of Laufer @foot{Laufer, J., "The Structure of Turbulence in Fully Developed Pipe Flow", @i 2954(1953).} and himself @foot{Deissler, R.G., "Analytical and Experimental Investigations of Adiabatic Turbulent Flow in Smooth Tubes", @i 2138(1950).} His correlation was @equation{ u@+<+>= [H(y@+<+>)-H(y@+<+>-26)]@ovp<(>,y@-<0>@+[+]dy@+<+>/(1+.015u@+<+>y@+<+>[1-exp<-.015u@+"+"y@+"+">]) + (2.8 ln y@+<+> +3.8 with @equation{u@+<+>=u(4@ovp(o),Lg@-"c"@+"-1"D@+"-1"@uP@+"-1")@+".5", and y@+<+>=y(.25g@-"c"D@uP@ovp,@+"-1"L@+"-1"@ovp(u u@+<+> and y@+<+> are dimensionless velocity and displacement, respectively, as functions of density, tube length, tube diameter, pressure drop, and viscosity. H is Heaviside's function, often appelated the unit step function. Ocular inspection yields the accuracy measurement @equation{u@+<+>:=u@+<+> @u(+) 1.} This has recently been simplified via further discretisation into three zones, the viscous sublayer, the buffer zone and the turbulent core. @foot{ As appeared in, without direct reference, @i, McCabe, W.L., and Smith, J.C., 3rd.ed., NY:McGrawHill, 1976, p.95.} @equation{u@+<+>=y@+<+>[H(y@+<+>)-H(y@+<+>-5)] + [5lny@+<+> -3.05][H(y@+<+>-5)-H(y@+<+>-30)] + [2.457lny@+<+>+5.67]H(y@+<+>-30) indicated, however, that the discontinuities lack physical correspondence. Since no data or refernce is provided for the latter correlation and since ocular inspection indicates sufficient similarity, the accuracy of the former shall be assumed for the latter. @comment( Schlichting; Knudsen&Katz p 97,101-5,158-71) @Chap(The Proposed Correlation) @sec(Preliminary Correlation) A function was assumed and its constants were obtained numerically @foot{Marquardt-Levenberg iterative curve fitting algorithm, in: Knott, G.D., & Reece, D.K., MLAB:A Civilised Curve Fitting System, @i, @b<1>, p. 497-526, Brunel,UK(1972); Knott, G.D., @i< Computer Programs in Biomedicine>, @b<10>(1979)271-280; Knott, G.D., & Reece, D.K., @i, interactive program in SAIL, for DEC PDP-10 systems, Laboratory of Statistical and Mathematical Methodology, DCRT, NIH, Bethesda, Md.(1980). The curve fitting performed later in this document were obtained via MLAB's Marquardt-Levenberg error optimisation capabilities in which: (1) The standard errors are standard deviations when the model is linear in its coefficients; (2) Dependency values positively measure intercoefficional dependency and uniqueness of fit, i.e., the sharpness of the stationary point; (3) Sum of squares are a chi-squared statistic with degrees of freedom being the number of observations less the number of coefficients; (4) RMS error is a dimensional goodness of fit measure equal to the square root of the chi-square/degrees-of-freedom; (5) t-statistic may be calculated by dividing the coefficient by the standard error; (6) r-squared may be proxied via 1-RMS-error/Best-data-value. }, yielding, @equation{u@+<+>=y@+<+>(-.452-.813x10@+<-4>y@+<+>)+(8.44+.0721y@+<+>)lny@+<+>-9.15+11.5/y@+<+> t=[-40.6,-18.5,111,35.6,-66.7,57 @u(+)(.23=1.645*.142) |95% confidence | 1NOT SIGNIF} RMS ERROR= .936093 FINAL SUM OF SQUARES= 334.735 @end(verbatim) @caption(Correlations with MLAB) @end(figure)