From engine integration to cabin noise: drivers to accurate interior noise evaluations
The present paper addresses the topic of of end-to-end cabin noise aero-vibro-acoustic prediction for civil aircraft. Through an overview of Airbus cabin noise prediction means and related investigations, the sensitivity of cabin noise to key parameters at engine and aircraft levels is demonstrated, highlighting the need for high fidelity numerical and experimental capabilities as well as integrated ways of working between engine and aircraft manufactureres in the frame of engine design to cabin noise.
A projection and condensation method for aerospace noise and vibration engineering
A condensation method based on the U-vectors from Singular Value Decomposition is applied on aeroacoustics and structural dynamics data. The aim of the condensation is to make the process of cabin noise levels estimates and noise control design more efficient. The suggested method is allowing a reduction of the number of load cases used for vibro-acoustic analyses, and hence significantly reduces the time and efforts for vibration predictions and subsequent cabin noise estimates. Application of the method is made to aeroacoustic predictions for a Counter Rotating Open Rotor propulsion system, and for structural response data for an aircraft test section available at AIRBUS GmbH, Hamburg, Germany.
New Sweet-Tasting C21-Pregnane Glycosides from Pericarps of Myriopteron extensum.
Ten novel C21 pregnane glycosides, extensumside C-L (1-10), were isolated as highly sweet-tasting substances from the edible pericarps of Myriopteron extensum (Wight) K. Schum by sensory-guided fractionation and purification. Their structures were determined through 1D and 2D NMR, such as HSQC, HMBC, 1H-1H COSY, HSQC-TOCSY, and ROESY, as well as other spectroscopic analysis combined with chemical evidence. These compounds shared the same aglycone, 3β,16α-dihydroxy-pregn-5-en-20-one, and contained the deoxysugar chain and the glucose chain which were linked to C-3 and C-16 of the aglycone, respectively. The sweetness potency was evaluated by a human sensory panel test and preliminary structure-taste relationship was discussed. The sweetness intensities of these compounds are between 50 and 400 times greater than that of sucrose. Furthermore, quantitation analyses of compounds 1, 3, 4, and 6 in different parts of M. extensum indicated that the concentrations of these sweet components in the pericarps are obviously higher than those in stems and roots.