ON DESIGNING IMPEDANCE TUBE WITH GRAZING FLOW

Designing Vacuum Tube Circuits

Investigation on Turbulent Nanofluid Flow in Helical Tube in Tube Heat Exchangers

In this study, the thermal characteristics of turbulent nanofluid flow in a helical tube in the tube heat exchanger (HTTHE) were assessed numerically through computational fluid dynamics (CFD) simulation. The findings of both the turbulent models: realizable k-epsion (k-ε) and re-normalisation group (RNG) k-epsilon were compared. The temperature distribution contours show that realizable and RN...

Acoustic characterisation of liquid foams with an impedance tube.

Acoustic measurements provide convenient non-invasive means for the characterisation of materials. We show here for the first time how a commercial impedance tube can be used to provide accurate measurements of the velocity and attenuation of acoustic waves in liquid foams, as well as their effective "acoustic" density, over the 0.5-6kHz frequency range. We demonstrate this using two types of l...

Impedance of a Beam Tube with Small Corrugations

In accelerators with very short bunches, such as is envisioned in the undulator region of the Linac Coherent Light Source (LCLS)[1], the wakefield due to the roughness of the beam-tube walls can have important implications on the required smoothness and minimum radius allowed for the beam tube. Of two theories of roughness impedance, one yields an almost purely inductive impedance[2], the other...

Design and Evaluation of Modifications to the NASA Langley Flow Impedance Tube

The need to minimize fan noise radiation from commercial aircraft engine nacelles continues to provide an impetus for developing new acoustic liner concepts. If the full value of such concepts is to be attained, an understanding of grazing flow effects is crucial. Because of this need for improved understanding of grazing flow effects, the NASA Langley Research Center Liner Physics Group has in...