Modeling of viscous flows in two-dimensional turbomachinery cascade via viscous-inviscid interaction method

[Abstract]: A two-dimensional time-accurate time-marching viscous flow solver employing the viscous-inviscid interaction method suitable for turbomachinery applications is described. The inviscid main flow solver uses the second-order accurate cellvertex finite-volume spatial discretisation and fourth-order accurate Runge-Kutta temporal integration. The viscous effect due to boundary layer development on the blade surfaces and wakes are modelled using an independent one-dimensional boundary layer subroutine capable of modelling laminar, transition and fully turbulent flows. The solver has been applied to subsonic, transonic and supersonic flow in a cascade of nozzle blades. The results are compared with the experimental data and they showed very good agreemen

Digital predictions of complex cylinder packed columns

A digital computational approach has been developed to simulate realistic structures of packed beds. The underlying principle of the method is digitisation of the particles and packing space, enabling the generation of realistic structures. Previous publications [Caulkin, R., Fairweather, M., Jia, X., Gopinathan, N., & Williams, R.A. (2006). An investigation of packed columns using a digital packing algorithm. Computers & Chemical Engineering, 30, 1178–1188; Caulkin, R., Ahmad, A., Fairweather, M., Jia, X., & Williams, R. A. (2007). An investigation of sphere packed shell-side columns using a digital packing algorithm. Computers & Chemical Engineering, 31, 1715–1724] have demonstrated the ability of the code in predicting the packing of spheres. For cylindrical particles, however, the original, random walk-based code proved less effective at predicting bed structure. In response to this, the algorithm has been modified to make use of collisions to guide particle movement in a way which does not sacrifice the advantage of simulation speed. Results of both the original and modified code are presented, with bulk and local voidage values compared with data derived by experimental methods. The results demonstrate that collisions and their impact on packing structure cannot be disregarded if realistic packing structures are to be obtained

Axisymmetric stagnation-point flow of a third-grade fluid over a lubricated surface

In this article, axisymmetric stagnation-point flow of a third-grade fluid over a disk lubricated with a power law fluid is considered. Due to thin lubrication layer of variable thickness, third-grade fluid experiences a partial slip on the surface. The flow problem is governed through a system of nonlinear partial differential equations with nonlinear boundary conditions. A nonsimilar solution is presented in this article by implementing hybrid homotopy analysis method. This method combines the features of homotopy analysis and shooting methods. The results varying from no-slip to full-slip case are discussed under the influence of pertinent parameters

Efecto de la hormona de crecimiento sobre los parámetros seminales, el hemograma parcial y el nivel de testosterona en búfalos Nili Ravi

The purpose of this trial was to examine the possible effects of exogenous growth hormone (GH) on semen quality, hematological variables and serum testosterone concentration in Nili Ravi buffalo. Bulls of the treatment group (n=3) were injected with recombinant GH 500 mg in a 15 day interval for 10 consecutive weeks, while bulls of control group (n=3) received equal volume of normal saline solution. Semen samples were collected twice per week and analyzed for physiological parameters. Blood samples collected fortnightly were analyzed for red blood cells count (RBC), hemoglobin concentration (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), white blood cell (WBC), neutrophils, lymphocytes, and serum testosterone levels. Data were analyzed statistically using t-test. Results indicated that GH treatment of Nili-Ravi buffaloes significantly (p<0.05) increased ejaculatory volume (8.8±0.2 vs 7.7±0.2 ml), sperm motility (72.6±0.4 vs 67.4±0.7%), mass activity (3.35±0.07 vs 2.52±0.08), sperm concentration (982.2±67.8 vs 731.9±50.5 million/ml), live sperm (80.1±0.3 vs 75.8±0.5%) and serum testosterone (4.02±0.21 vs 2.37±0.07 ng/ml) compared to control bulls. Among hematological variables, lymphocytes were increased (p<0.05), but MCV, WBC count, and neutrophils decreased (p<0.05). Hb, RBC and PCV remained unchanged. However, values of these variables were within normal ranges for buffalo bulls. In conclusion, treatment of Nili-Ravi bulls with GH improved semen quality and increased serum testosterone without ostensible adverse effects on the general state.El propósito de este ensayo fue examinar los posibles efectos de la hormona de crecimiento exógena (GH) sobre la calidad del semen, algunas variables del hemograma y la concentración de testosterona en suero de toros bubalinos Nili Ravi. Los búfalos del grupo tratado (n=3) fueron inyectados con 500 mg de somatotropina recombinante cada 15 días durante 10 semanas consecutivas, mientras que los del grupo control (n=3) recibieron igual volumen de solución fisiológica salina. Las muestras de semen fueron tomadas dos veces por semana y analizadas para evaluar los parámetros fisiológicos. Las muestras de sangre colectadas quincenalmente fueron analizadas para establecer el recuento de glóbulos rojos, la  concentración de hemoglobina, el hematocrito, el volumen corpuscular medio (MCV), recuento de glóbulos blancos (WBC), tasa de neutrófilos y linfocitos, así como los niveles séricos de testosterona. Los datos obtenidos fueron analizados estadísticamente por medio del test-t de Student. Los resultados indicaron que el tratamiento con somatotropina aumentó significativamente (p<0,05) el volumen eyaculado (8,8±0,2 versus 7,7±0,2 ml), la motilidad del semen (72,6±0,4 versus 67,4±0,7%), la actividad de masa (3,35±0,07 versus 2,52±0,08), la concentración de espermatozoides (982,2±67,8 versus 731,9±50,5 millones/ml), los espermatozoides vivos (80,1±0,3 versus 75,8±0,5%) y el nivel de testosterona sérica (4,02±0,21 versus 2,37±0,07 ng/ml), comparados con los animales controles. En el hemograma aumentaron los linfocitos (p<0,05) y disminuyeron variables como volumen corpuscular medio, recuento de leucocitos y tasa de neutrófilos (p<0,05). Hemoglobina, concentración de eritrocitos y hematocrito permanecieron inalterados. Todos los parámetros investigados se situaron dentro de los rangos normales para toros bubalinos. En conclusión, el tratamiento de búfalos Nili-Ravi con somatotropina mejoró la calidad del semen y aumentó la testosterona sérica, sin provocar ostensibles efectos adversos en el estado general de los toro