Study of Dynamic Interaction Between Low Re Aerodynamic Load and Flexible-Biomimetic Wings with Tailorable Stiffness by FSI Modeling

In the present work, we investigate dynamic interaction and response of flexible bio-inspired morphing wing structure to a low Reynolds aerodynamic load. The aspects of inspiration are as follows. First, the segmentation of the wing into rigid and flexible segments. Considering a leading edge constitution of bone and muscle. In addition to a flexible trailing edge composed of feathers. Second, the material properties provided by experimental biology in literature are adopted such as the bending stiffness and Young's modulus. The development of numerical models allowing non uniform distribution of properties are developed and implemented into an OpenFoam finite volume solver that couples fluid dynamics to a structural solid dynamics solver through the FSI interface. In the course of this work, the validation is performed for a NACA6409 airfoil considering a rigid segment of 40\% and flexible segment 60\% chord length in order to test the aero-structure behavior for an aerodynamic load of air flow at low Reynolds number of $\boldsymbol{5\times 10^5}$ for the fluid and feather inspired material properties. The results suggest that bio-inspired techniques can be reproduced in engineering configurations.Comment: This is the author's version of an article that has been published at 2023 AIAA SciTech Forum - 23-27 January 2023. The final version of record is available at: \url{https://arc.aiaa.org/doi/abs/10.2514/6.2023-0826

Low Reynolds number effect on CFD prediction of bio inspired aerodynamics

This work is motivated by the need for the implementation of the best numerical modelsfor low Reynolds flows and presents the state–of–the–art of the implemented models for thetransition of the laminar-turbulent predictions. The numerical models are applied to investigatethe aerodynamic characteristics and flow behavior around bird–like airfoils. Two DimensionalReynolds Averaged Navier Stokes (2D RANS) and Three-Dimensional Unsteady (3D U-RANS)methods are applied at a Reynolds number of105, whereas two-dimensional laminar simulationsand three-dimensional Large Eddy Simulation are employed for the known Owl-like airfoil atReynolds number of2.3×104. The numerical results of flow fields around Owl-like airfoil atthe latter Reynolds number using two-dimensional laminar and 3DLES predict correctly theunsteadiness of the aerodynamic coefficients. The 2D and 3D RANS methods are predicting wellthe aerodynamics characteristics for the man-made-bird-like airfoil at Reynolds number of105

Molecular epidemiology of MRSA in 13 ICUs from eight European countries

Objectives: The European epidemiology of MRSA is changing with the emergence of community-associated MRSA (CA-MRSA) and livestock-associated MRSA (LA-MRSA). In this study,we investigated the molecular epidemiology of MRSA during 2 years in 13 ICUs in France, Greece, Italy, Latvia, Luxemburg, Portugal, Slovenia and Spain. Methods: Surveillance cultures for MRSA from nose and wounds were obtained on admission and twice weekly from all patients admitted to an ICU for ≥3 days. The first MRSA isolate per patient was genotyped in a central laboratory by MLST, spa typing, agr typing and SCCmec (sub)typing. Risk factors for patients with an unknown history of MRSA colonization were identified. Results: Overall, 14390 ICU patients were screened, of whom 8519 stayed in an ICU for ≥3 days. Overall MRSA admission prevalence was 3.9% and ranged from 1.0% to 7.0% for individual ICUs. Overall MRSA acquisition rate was 2.5/1000 patient days at risk and ranged from 0.2 to 8/1000 patient days at risk per ICU. In total, 557 putative MRSA isolates were submitted to the central laboratory for typing, of which 511 (92%) were confirmed as MRSA. Each country had a distinct epidemiology, with ST8-IVc (UK-EMRSA-2/-6, USA500) being most prevalent, especially in France and Spain, and detected in ICUs in five of eight countries. Seventeen (3%) and three (70 years and hospitalization within 1 year prior to ICU admission. Conclusions: The molecular epidemiology of MRSA in 13 European ICUs in eight countries was homogeneous within, but heterogeneous between, countries. CA-MRSA and LA-MRSA genotypes and Panton-Valentine leucocidin-producing isolates were detected sporadically