In this work the performance of Reynolds Averaged Navier-Stokes (RANS) simulations to predict the flow structure developed by the presence of a sidewall obstacle in a uniform open-channel shallow flow is discussed. The tested geometry was selected due to its important role in several fluvial applications, such as the control of riverbank erosion and the creation of improved ecological conditions in river restoration applications. The results are compared against experimental laboratory velocity fields obtained after Large Scale Particle Image Velocimetry (LSPIV) measurements. It is shown that the length of reattachment of the separated shear layer generated by the obstacle is well predicted by a Reynolds Stress Model, while classical two-equation models show important limitations. All the performed RANS simulations are unable to properly predict the formation of a secondary gyre region, which develops immediately downstream the obstacle.
Let X be a connected closed manifold and f a self-map on X. We say that f is almost quasi-unipotent if every eigenvalue λ of the map f∗k (the induced map on the k-th homology group of X) which is neither a root of unity, nor a zero, satisfies that the sum of the multiplicities of λ as eigenvalue of all the maps f∗k with k odd is equal to the sum of the multiplicities of λ as eigenvalue of all the maps f∗k with k even. We prove that if f is C 1 having finitely many periodic points all of them hyperbolic, then f is almost quasi-unipotent.
We characterize prime submodules of $R\times R$ for a principal ideal domain $R$ and investigate the primary decomposition of any submodule into primary submodules of $R\times R.$.
A brief pulse' of red (R) radiatíon increased actívity and protein content of phosphoenolpyruvate carboxylase (PEPC): diis increase was inhibited by cycloheximide. The efifect of R was far-red pulse (FR) reversible when R was followed inunediately (but not after 24 h) by FR. Thus phytochrome was involved in PEPC regulatíon in etiolated maize leaves. Both a lag phase and a saturation exist in the process of R induction of PEPC synthesis: the highest PEPC acitívity was obtained 24 h after R. Etiolated maize leaves of different age showed different sensitivity to R: the highest sensitivity was found in 5 d-old seedlings. 5 min of R was sufficient for inducing PEPC synthesis, and no additíonal increases were obtained in actívity and protein content of PEPC when the R tíme was prolonged.