Publication

Abstract : Available experimental data on friction in smooth rectangular channels were analyzed by a researcher and arrived at the relationship 1/√f′ = 2 log R√f′ - 0.8, where R = 4VR/v and f′ = f·ψp(P/R) for channels and f′ = f for smooth pipes. ψp(P/R) is a shape parameter. Values of P/R when b/y lt; 2 were indicated by an asterisk, and a relationship was obtained between P/R and ψp(P/R). Two researchers analyzed the same data that were used by another researcher and concluded that two functions ψ1(P/b) = √P/b and ψ2(b/y) are required to reflect the shape parameter. However, they combined and obtained ψK = ψ1/ψ2 = f/f′. ψ2(b/y) was calculated and plotted against b/y. They noted that ψK ≡ 1/ψp, but maintained that there is no good relationship between ψp and P/R. In the present study, it is shown that based on the curve, the equation connecting ψp(P/ R) and P/R could be obtained, which fits the curve within 1% error. A plot P/R versus ψp(P/R) is given for ready use.