The semi empirical scaling law by Nelson and Morfey [1] predicts the noise generation from constrictions in ducts with low Mach number flows. The results presented here demonstrate that the original model loose accuracy for constrictions of high pressure loss. An extension based on a momentum flux assumption of the dipole forces is suggested and is evaluated against measurement results for orifice geometries of higher pressure loss than earlier evaluated. A prediction model including constrictions at flow duct terminations is also suggested. Improved accuracy for the predictions of the new model are found for orifice geometries of both high and low pressure loss inside and at end of ducts. The extended model is finally evaluated by measurementson a regular ventilation air terminal device.
Revisiting the Nelson–Morfey scaling law for flow noise from duct constrictions
Journal of sound and vibration ; 357 ; 233
2015
Article (Journal)
English
Heat Flow Through Conical Constrictions
AIAA | 1980
|Thermal conductance of two-dimensional constrictions
AIAA | 1968
|Thermal Conductance of Two-Dimensional Constrictions
AIAA | 1969
|