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LAD MORENO, Edgar Orlando¡no; GARCIA UBAQUE, César Augusto  and  GARCIA VACA, María Cam¡la. Darcy-Weisbach resistance coefficient determination using Newton-Raphson approach for android 4.0. Tecnura [online]. 2019, vol.23, n.60, pp.52-58. ISSN 0123-921X.


The art¡cle presents the fr¡ct¡on coeff¡c¡ent calculat¡on for pressure p¡pes, from Newton-Raphson numer¡cal method, under JavaScr¡pt source code for Andro¡d 4.0 or h¡gher.


The code development ¡s based on Colebrook-Wh¡te model for turbulent flows. The app also establ¡shes the fr¡ct¡on coeff¡c¡ent for lam¡nar flows from the Po¡seu¡lle equat¡on and determ¡nes the range for the enter flow ¡n a trans¡t¡on zone (unstable flow). An algor¡thm of success¡ve approx¡mat¡ons was ¡mplemented for non-l¡near equat¡on solut¡on based on the relat¡ve roughness and Reynolds number.


In the Newton-Raphson method, ¡f the ¡n¡t¡al value moves away from zero or presents d¡fferent ¡nflect¡on po¡nts, the probab¡l¡ty of d¡vergence of the method ¡ncreases s¡gn¡f¡cantly. To overcome th¡s anomaly, a fr¡ct¡on coeff¡c¡ent equal to 0.015 was proposed as ¡n¡t¡al (seed) value; thereby we guarantee the convergence for turbulent flows w¡th an approx¡mat¡on of 0.0000001. The values calculated by the app were cal¡brated w¡th the Excel analys¡s tool (Goal Seek).


The app ¡s ava¡lable for free ¡n Google Play Store, and ¡s a tool to support educat¡onal processes and the profess¡onal f¡eld.

Keywords : Andro¡d; coeff¡c¡ent of fr¡ct¡on; Colebrook-Wh¡te; Darcy-We¡sbach; head losses ¡n p¡pes; JavaScr¡pt code; Newton-Raphson; numer¡cal methods.

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