The Quest for the Ideal Darcy-Weisbach Friction Factor Equation from the Perspective of a Building Services Engineer

Bacoţiu Ciprian 1
  • 1 Technical University of Cluj-Napoca, , 400114, Cluj-Napoca, Romania


The calculation of the friction factor involved in the Darcy-Weisbach equation has a key role in the accurate assessment of distributed head losses. For the turbulent flow regime, this friction factor was mathematically expressed in the form of the Colebrook-White (C-W) equation, widely accepted by engineers and scientists. Nevertheless, the C-W equation is an implicit one and must be solved using numerical methods. This is a major disadvantage for the average engineer, who always prefers an explicit equation which could be easily integrated into his familiar spreadsheet environment. The present paper is investigating some of the most used explicit alternatives to the C-W equation, with respect to several case scenarios taken from typical Building Services hydraulic calculations.

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  • [1] Florea J., Seteanu I., Zidaru Gh., Panaitescu V. (1982), Mecanica fluidelor şi maşini hidropneumatice, Editura Didactică şi Pedagogică, Bucureşti.

  • [2] Isbăşoiu E. C. Gh., Georgescu S.-C. (1995), Mecanica fluidelor, Editura Tehnică, Bucureşti.

  • [3] Papaevangelou G., Evangelides C., Tzimopoulos C. (2010), A new explicit relation for the friction coefficient in the Darcy–Weisbach equation. In: Protection and Restoration of the Environment X, University of Ioannina (Greece) & Stevens Institute of Technology (New Jersey), Corfu, Greece, pp. 1-7.

  • [4] Popescu F., Paraschiv L.S., Paraschiv S., Frătița M., Alexandru I. (2018), Mecanica fluidelor - Îndrumar de laborator, Editura Fundaţiei Universitare “Dunărea de Jos” din Galaţi.

  • [5] S. Genić, I. Arandjelović, P. Kolendić, M. Jarić, N. Budimir, V. Genić (2011), A Review of Explicit Approximations of Colebrook’s Equation, FME Transactions, vol. 39, pp. 67-71, Belgrade, Serbia.


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