Turbulent Flow Friction Factor Calculation Using a Mathematically Exact Alternative to the Colebrook–White Equation

New explicit correlations for turbulent flow friction factor

“…Also, approximations proposed by Romeo et al (2002), Buzzelli (2008), more complex form of approximation by Serghides (1984), more complex form of approximation by Zigrang and Sylvester (1982) and approximation by Vatankhah and Kouchakzadeh (2009) will always give more accurate results than those calculated by approximations proposed by Fang et al (2011) as shown in figure 2. On the other hand as shown in figure 3, inconclusive conclusion of accuracy in general can be found by using of approximation by Barr (1981), simpler form of approximation by Serghides (1984), approximation by Chen (1979), Sonnad and Goudar (2006), Papaevangelou et al (2010) and by using simpler form of approximations by Zigrang and Sylvester (1982), all versus approximation by Fang et al (2011). Approximation proposed by Relative error of certain approximations to the Colebrook equation was also presented in Gregory and Fogarasi (1985) and Zigrang and Sylvester (1985).…”

“…Colebrook's formula can be solved in iterative procedure since it contains implicitly given flow friction factor. Also, numerous explicit approximations can be used to substitute implicit Colebrook's equation which cannot be solved for unknown flow friction factor with no 3 approximate calculus (Moody, 1947;Wood, 1966;Eck, 1973;Churchill, 1973;Swamee and Jain, 1976;Jain, 1976;Churchill, 1977;Chen, 1979;Round, 1980;Barr, 1981;Zigrang and Sylvester, 1982;Haaland, 1983;Serghides, 1984;Manadilli, 1997;Romeo et al 2002;Sonnad and Goudar, 2006;Buzzelli, 2008;Avci and Karagoz, 2009;Vatankhah and Kouchakzadeh, 2009;Papaevangelou et al, 2010;Brkić, 2011a,b;Fang et al 2011;Ghanbari et al, 2011). Two novel explicit approximations to the Colebrook's formula will be shown in further text.…”

Evolutionary Optimization of Colebrook’s Turbulent Flow Friction Approximations

“…1]. Relevant parameters and errors related to Approximation by Brkić [19] after and before optimization (6) ( ) ( [43,44] changing parameter ɑ11 to A11-0.31 slightly change model of Sonnad and Goudar [26]. They used line fitting tool for optimization.…”

Perda de carga em conectores iniciais da irrigação localizada

“…Para escoamento em tubos comerciais rugosos é a equação mais utilizada para calcular , 1976;SERGHIDES, 1984;PORTO, 1998;ROMEO et al, 2002;YOO;SINGH, 2005;SONNAD;GOUDAR, 2006).…”