Influence of swirl on the discharge coefficients of sonic nozzles

Sound Production due to Swirl-Nozzle Interaction: Model-Based Analysis of Experiments

“…The model predicts an essentially quadratic swirl number dependence of the generated sound amplitude. This is verified by the unsteady experimental results of Kings and Bake [5] and the steady experiments of Dutton [20] and Yoo et al [21]. However, the steady experiments of Dutton [20] and Yoo et al [21] and numerical results of Dutton [20] predict a 2.5 times lower reduction of the mass flow through the nozzle as the analytical model of Gany et al [13] and van Holten et al [15]used here.…”

“…8, this produces satisfactory agreement with Dutton's data [20]. Note that Dutton's results [20] agree with Yoo's et al independently obtained experimental results [21].…”

“…In practice this leads to the discharge coefficient not reaching the value one. This is clearly visible in the measurements reported by Yoo et al [21] (Figs. 9, 10, 11 and 12 in Ref.…”

“…9, 10, 11 and 12 in Ref. [21]) which demonstrate that the measured C D will remain about 0.7 % lower than one, even for zero swirl conditions. Accounting for this, Dutton [20] shows results in terms of C D /C D0 , which equals one when S th = 0.…”

“…Data Experimental results found in the literature [19][20][21], are presented in terms of the discharge coefficient C D , defined as…”