Congrès International d'Architecture Moderne

About: Congrès International d'Architecture Moderne is a based out in . It is known for research contribution in the topics: Boundary value problem & Jet (fluid). The organization has 393 authors who have published 403 publications receiving 4104 citations.

Incidence and viability of Acremonium endophytes in tall fescue accessions from North Spain

Abstract: The tall fescue (Festuca arundinacea Schreb.) seed collection of the Centro de Investigaciones Agrarias de Mabegondo was surveyed to determine Acremonium infection rates. One hundred seeds from each of 19 accessions were microscopically examined for endophyte. Seventeen accessions (90%) contained endophyte with a range of 7 to 100%. Leaf sheaths of seedlings from the infected accessions were examined to determine the percentage of infection with viable endophyte. Only seven (41%) of the seventeen infected accessions collected and stored in 1995 at 4°C and 45–50% relative humidity contained viable endophyte with a range of 70 to 100%. While existing germplasm collections of Festuca arundinacea can provide only a small basis of Acremonium germplasm for study, newly collected Festuca arundinacea accessions will offer a greater diversity of Acremonium genotypes.

Investigation of noise generation by turbulent jets on the basis of numerical simulation of unsteady flow in mixing layers

Abstract: In the previous experimental studies it was concluded that the turbulent jet noise is produced by large-scale motions in the mixing layer induced by turbulence intermittence. The burden of this numerical simulation is the validation of these conclusions. As a result of numerical calculations, the “instantaneous” flow patterns and the parameter distributions in the initial regions of turbulent jets are obtained. On the basis of this information the flow dynamics are investigated. In the jet flow there are observable slowly transforming low static pressure regions and zones of elevated static pressure. These regions are displaced at the convection velocity. The inflow induced by the low pressure in the mixing layer has streamlines entering into the low pressure zones and flowing around the elevated pressure zones. The motion of the zones of the static pressure varying along the flow produces velocity disturbances in the induced external flow. The succession of the transformations of the intermittence-induced static pressure disturbances into sound waves is determined. This transformation occurs in the regions occupied by the ejected air.

Uncertainty quantification and robust design optimization applied to aircraft propulsion systems

Abstract: The standard way of formulating optimization problems applied to aircraft design is based on the assumption that the underlying system is deterministic, i.e., that the knowledge associated with the design variables and with the system dynamic is not characterized by uncertainty. However, in real conditions randomness impacts the formulation of the design process in multiple ways and the system outputs (i.e., the key performance indicators and the design constraints) are also affected by uncertainty. A system designed under deterministic assumptions may therefore have an unreliable behavior due to the fluctuations associated with the input random variables. This problem can be tackled by adopting a probabilistic approach and re-formulating the design optimization problem with an additional set of constraints associated with the robustness / reliability of the target system. This work addresses the problem of optimizing the geometry of a turbofan engine nacelle subject on reliability constraints. An advanced, machine-learning based framework is adopted in order to (a) investigate the system behavior through an adaptive design of experiments technique and (b) build accurate surrogate models of the system dynamics. These surrogate models are then employed to run a set of probabilistic studies at an affordable computational cost. The results of these investigations include (a) an extensive suite of analyses aimed at characterizing the uncertainty associated with the output quantities of interest; (b) a robust optimization of the engine nacelle geometry and (c) an assessment of the reliability of the optimized design. The improved performance and reliability of the design, together with the limited number of overall system evaluations required to run the analyses, demonstrate the effectiveness and the engineering applicability of the proposed approach.