THE EFFECTS OF VELOCITY RATIO ON THE LARGE SCALE COHERENT STRUCTURES IN FREE SHEAR LAYERS

The velocity ratio of a free shear layer has an important influence on the spatial development of the large scale coherent structures in the layer. In this study, numerical simulations are performed to get an insight into this problem. The obtained numerical results agree quite well with those of a linear inviscid stability theory and the available experimental data.

A Study in Search of Interconnection between Surface Parameters and Surrounding Synoptic And Subsynoptic Features

The paper reveals that the variations in parameters like u *, the scaling velocity and θ*. The scaling temperature during the various phases of monsoon might be linked with subsynoptic features. The rise in u * is mainly connected with the presence of lower tropospheric cyclonic vorticity over a subsynoptic scale of the site. However the variations in θ. is mainly linked with the various phases of monsoon and θ * shows a sharp rise in presence of low level convective cloud.Besides the correlation studies of u and u., θv and θv, θv-θv0 and θv, * are undertaken. The correlation between θv and θv * is poor. In other two cases correlations are good. Besides u / u * has shown good coefficient of variation values within the ξ range.

Parameterization of Sheared Entrainment in a Well-developed CBL.PartⅡ:A Simple Model for Predicting the Growth Rate of the CBL

Following the parameterization of sheared entrainment obtained in the companion paper, Liu et al. （2016）, the present study aims to further investigate the characteristics of entrainment, and develop a simple model for predicting the growth rate of a well-developed and sheared CBL. The relative stratification, defined as the ratio of the stratification in the free atmosphere to that in the entrainment zone, is found to be a function of entrainment flux ratio （Ae）. This leads to a simple expression of the entrainment rate, in which Ae needs to be parameterized. According to the results in Liu et al. （2016）, Ae can be simply expressed as the ratio of the convective velocity scale in the sheared CBL to that in the shear-free CBL. The parameterization of the convective velocity scale in the sheared CBL is obtained by analytically solving the bulk model with several assumptions and approximations. Results indicate that the entrainment process is influenced by the dynamic effect, the interaction between mean shear and environmental stratification, and one other term that includes the Coriolis effect. These three parameterizations constitute a simple model for predicting the growth rate of a well-developed and sheared CBL. This model is validated by outputs of LESs, and the results show that it performs satisfactorily. Compared with bulk models, this model does not need to solve a set of equations for the CBL. It is more convenient to apply in numerical models.

Anterior subcutaneous transposition of the ulnar nerve improves neurological function in patients with cubital tunnel syndrome

Although several surgical procedures exist for treating cubital tunnel syndrome, the best surgical option remains controversial. To evaluate the efficacy of anterior subcutaneous transposition of the ulnar nerve in patients with moderate to severe cubital tunnel syndrome and to analyze prognostic factors, we retrospectively reviewed 62 patients（65 elbows） diagnosed with cubital tunnel syndrome who underwent anterior subcutaneous transposition. Preoperatively, the initial severity of the disease was evaluated using the Mc Gowan scale as modified by Goldberg： 18 patients（28%） had grade IIA neuropathy, 20（31%） had grade IIB, and 27（42%） had grade III. Postoperatively, according to the Wilson ＆ Krout criteria, treatment outcomes were excellent in 38 patients（58%）, good in 16（25%）, fair in 7（11%）, and poor in 4（6%）, with an excellent and good rate of 83%. A negative correlation was found between the preoperative Mc Gowan grade and the postoperative Wilson ＆ Krout score. The patients having fair and poor treatment outcomes had more advanced age, lower nerve conduction velocity, and lower action potential amplitude compared with those having excellent and good treatment outcomes. These results suggest that anterior subcutaneous transposition of the ulnar nerve is effective and safe for the treatment of moderate to severe cubital tunnel syndrome, and initial severity, advancing age, and electrophysiological parameters can affect treatment outcome.

Validated scale-up procedure to predict blockage condition for fluidized dense-phase pneumatic conveying systems

This paper presents results of an ongoing investigation into modelling fluidized dense-phase pneumatic conveying of powders. For the reliable design of dense-phase pneumatic conveying systems, an accurate estimation of the blockage boundary condition or the minimum transport velocity requirement is of sig- nificant importance. The existing empirical models for fine powder conveying in fluidized dense-phase mode are either based on only a particular pipeline and product or have not been tested for their accuracy under a wide range of scale-up conditions. In this paper, a validated test design procedure has been devel- oped to accurately scale-up the blockage boundary with the help of a modelling format that employs solids loading ratio and Froude number at pipe inlet conditions using conveying data of two different samples of fly ash, electro-static precipitation （ESP） dust and cement （particle densities： 2197-3637 kgJm3; loose poured bulk densities： 634-1070kg/m3; median size： 7-30 l^m）. The developed models （in power func- tion format） have been used to predict the blockage boundary for larger diameter and longer pipelines （e.g. models based on 69 mm I.D. ~ 168 m long pipe have been scaled up to 105 mm I.D. and 554 m length）. The predicted blockage boundaries for the scale-up conditions were found to provide better accuracy compared to the existing models.

NUMERICAL SIMULATION OF EXTREMELY HEAVY RAIN AND MESO-β SCALE LOW VORTEX IN INVERTED TYPHOON TROUGH

Large-scale and mesoscale analyses are made for extremely heavy rain (EHR) and meso-β scale low vortex (MSLV) in Jiading District of Shanghai Municipality during 6-7 July 2001.It is shown that the EHR forms in the situation of northern westerly trough linking together with southern inverted typhoon trough at northwest side of the West Pacific Ocean subtropical high. Numerical simulation is made using a 21-layer improved REM (regional η coordinate model) for this course.The results show that the precipitation forms earlier than MSLV.and the strong convergence in wind velocity mate (WVM) triggers the strong precipitation.The formative reasons of WVM.especially the weak wind velocity center are discussed,and the formative mechanisms of the MSLV and EHR are discussed using high spatial and temporal resolution model- output physical fields.The results show that the heavy rain releases latent heat and warms the air column,and enhances the low level positive vorticity that existed before.Then it causes the formation of MSLV.There is a positive feedback mechanism between low vortex and precipitation,so CISK must be an important mechanism.

An advanced evaluation of the mechanistic scale-up methodology of gas-solid spouted beds using radioactive particle tracking

We implemented for the first time our radioactive particle tracking as an advanced noninvasive tech- nique to further evaluate and validate our newly developed mechanistic scale-up methodology based on matching the radial profile of the gas holdup.Two spouted beds with diameters of 0.076 and 0.152 m were used. Three sets of conditions were implemented; i.e., conditions of the reference case, conditions that provided a gas-holdup radial profile similar to that of the reference case, and conditions that provided a gas-holdup radial profile dissimilar to that of the reference case. The results confirm the validation of the scale-up methodology in terms of obtaining closer dimensionless values and radial profiles of compo- nents of the particle velocity, normal stress, shear stress, and turbulent kinetic energy, The results further advance the understanding of gas-solids spouted beds, provide deeper insight into the solids dynamics of the beds and present important benchmarking data for validating computational fluid dynamics codes and models.