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Large eddy simulations of a three-dimensional (3D) compressible parallel jet flow at Mach number of 0.9 and Reynolds number 2000 are carried out. Four subgrid-scale (SGS) models, namely, the standard Smagorinsky model (SM), the selective mixed scale model (SMSM), the coherent-structure Smagorinsky model (CSM) and the coherent-structure kinetic-energy model (CKM) are employed, respectively, and compared. The purpose of the study is to compare the SGS models and to find their suitability of predicting the flow transition in the potential core of the jet, and so as to provide a reference for selecting SGS models in simulating compressible jet flows, which is a kind of proto-type flow in fluid dynamics and aeroacoustics. A finite difference code with fourth-order spatial and very low storage third-order explicit Runge-Kutta temporal schemes is introduced and employed for calculation. The code, which was previously designed for simulating shock/boundary-layer interactions and had been widely validated in simulating a variety of compressible flows, is rewritten and changed into parallelized using the OpenMP protocol so that it can be run on memory-shared multi-core workstations. The computational domain size and the index of LES resolution quality are checked to validate the simulations. Detailed comparisons of the four SGS models are carried out. The results of averaged flow-field including the velocity profiles and the developments of shear-layer, the instantaneous vortical flows and the viscous dissipation, the predicted turbulence statistics and the balances of momentum equation are studied and compared. The results show that although the normalized developed velocity profiles are well predicted by the four SGS models, the length of the potential core and the development of the shear-layer reveal that the SM has excessive SGS viscosity and is therefore too dissipative to correctly predict the flow transition and shear-layer expansion. The model smears small vortical scales and lowers down the effective Reynolds number of the flow because of the over-predicted SGS viscosity and dissipation. The turbulence statistics and the balances of momentum equation have also confirmed the excessive dissipation of the SM. The CKM is also found to over-predict the SGS viscosity. Compared with these two models, the SMSM and the CSM have performed well in predicting both the averaged and the instantaneous flow-fields of the compressible jet. And they are localized models which are computationally efficient and easy for coding. Therefore, the SMSM and the CSM are recommended for the LES of the compressible Jet.

This paper presents the thermo-magneto-electro-elastic (thermo-MEE) field in an annular plate of heterogeneous multiferroic composite medium subjected to thermal loadings uniformly distributed on the main boundaries. As a prior, the temperature distribution is determined by solving the thermo-conduction equation. Then, the direct displacement method is employed to derive the coupling thermo-MEE field. Finally, numerical calculations are performed to validate the present analysis and to investigate the influence of the material heterogeneity and the multi-field coupling. The present solutions can be readily reduced to those for circular plate upon letting the inner radius tend to zero. The obtained solutions may serve as a benchmark to various numerical codes and simplified analyzes, since no ad hoc hypothesis is adopted in the present work. [ABSTRACT FROM AUTHOR]

The structural response of coexisting multiple martensites to stress field in a Ni–Mn–Ga multifunctional alloy was investigated by the in situ high-energy x-ray diffraction technique. Stress-induced transformation between coexisting multiple martensites was observed at 110 K, at which five-layered modulated (5M), seven-layered modulated (7M) and non-modulated (NM) martensites coexist. We found that a tiny stress of as low as 0.5 MPa could trigger the transformation from 5M and 7M martensites to NM martensite and this transformation is partly reversible. Besides the transformation between coexisting multiple martensites, rearrangement of martensite variants also occurs during loading, at least at high stress levels. The present study is instructive for designing advanced multifunctional alloys with easy actuation. [ABSTRACT FROM AUTHOR]

2C is a highly conserved picornaviral non-structural protein with ATPase activity and plays a multifunctional role in the viral life cycle as a promising target for anti-picornavirus drug development. While the structure-function of enteroviral 2Cs have been well studied, cardioviral 2Cs remain largely uncharacterized. Here, an endogenous ATP molecule was identified in the crystal structure of 2C from encephalomyocarditis virus (EMCV, Cardiovirus A). The ATP is bound into the ATPase active site with a unique compact conformation. Notably, the γ-phosphate of ATP directly interacts with Arg311 (conserved in cardioviral 2Cs), and its mutation significantly inhibits the ATPase activity. Unexpectedly, this mutation remarkably promotes 2C self-oligomerization and viral replication efficiency. Molecular dynamic simulations showed that the Arg311 side chain is highly dynamic, indicating it may function as a switch between the activation state and the inhibition state of ATPase activity. A hexameric ring model of EMCV 2C full length indicated that the C-terminal helix may get close to the N-terminal amphipathic helices to form a continuous positive region for RNA binding. The RNA-binding studies of EMCV 2C revealed that the RNA length is closely associated with the RNA-binding affinities and indicated that the substrate may wrap around the outer surface of the hexamer. Our studies provide a biochemical framework to guide the characterization of EMCV 2C and the essential role of arginine in cardioviral 2C functions., Importance: Encephalomyocarditis virus (Cardiovirus A) is the causative agent of the homonymous disease, which may induce myocarditis, encephalitis, and reproductive disorders in various mammals. 2C protein is functionally indispensable and a promising target for drug development involving broad-spectrum picornaviral inhibitors. Here, an endogenous ATP molecule with a unique conformation was discovered by a combination of protein crystallography and high-performance liquid chromatography in the encephalomyocarditis virus (EMCV) 2C structure. Biochemical and structural characterization analysis of EMCV 2C revealed the critical role of conserved Arg311 in ATPase activity and self-oligomerization of EMCV 2C. The viral replication kinetics and infectivity study suggested that the residue negatively regulated the infectivity titer and virus encapsulation efficiency of EMCV and is, therefore, crucial for 2C protein to promote viral replication. Our systemic structure-function analysis provides unique insights into the function and regulation mechanism of cardioviral 2C protein., Competing Interests: The authors declare no conflict of interest.