The rotor-stator interaction and the corresponding pressure fluctuations represent one of the sources of pressure and load fluctuations on the rotating parts of rotating machineries. The high-Reynolds flow is subject to rotation in the comparably large vaneless space of axial turbines, causing wake interaction and wake dissipation in this region. This increases the level of flow complexity in this region. This study examined the effect of the flow condition entering the spiral casing on the flow condition within the distributor and the runner and the physical source of pressure fluctuations exerted on the runner of a Kaplan turbine model. Simulations were performed within the water supply system, including the upstream tank, penstock, and the Francis turbines, the level of entering the spiral casing; the results were compared with laser Doppler anemometry (LDA) results. The results were considered as the inlet boundary condition for simulation of the turbine model from the spiral inlet to the draft tube outlet to investigate the flow condition within the distributor and the runner. The CFD simulations showed that the water supply system induces inhomogeneity to the velocity distribution at the spiral inlet. However, the flow condition does not affect the pressure fluctuations exerted on the runner blades due to the rotor-stator interactions. Moreover, the dominant frequencies exerted on the runner blades were accurately approximated although the amplitudes of the fluctuations were underestimated.

Kidney has a hierarchy of nephrons on the vascular arteriole tree consisting of nephron groups that interact with neighbourhoods. The kidney modeling approach for the pressure dynamics is complex in mathematical and simulation models for paired and impaired nephrons. CA rules have been developed for multi nephron kidney model from individual nephron CA rules using cumulative algorithm based on additive cellular automata and modular arithmetic. The global emergent properties obtained from CA rules depict the pressure dynamics of the multi-scaled nephron network mode up to ten lakh nephrons, clearly illustrating the nephron’s behaviour that has been captured from the experimental analysis. Regular oscillation as normotensive behaviour and irregular oscillations as hypertensive behaviour have been observed in 30000 and 1000000 nephron network models for different cases. The chaotic oscillations have been observed in the 30000-nephron kidney which leads to chronic kidney disease. Studying the causes and effects of renal diseases due to impairment of nephrons using CA kidney models leads to improvement in the early diagnosis and treatment.

This paper is devoted to the second-order closure for compressible turbulent flows with special attention paid to modeling the pressure-strain correlation appearing in the Reynolds stress equation. This term appears as the main one responsible for the changes of the turbulence structures that arise from structural compressibility effects. The structure of the gradient Mach number is similar to that of turbulence, therefore this parameter may be appropriate to study the changes in turbulence structures that arise from structural compressibility effects. Thus, the incompressible model (LRR) of the pressure-strain correlation and its corrected form by using the turbulent Mach number, fail to correctly evaluate the compressibility effects at high shear flow. An extension of the widely used incompressible model (LRR) on compressible homogeneous shear flow is the major aim of the present work. From this extension the standard coefficients Ci became a function of the compressibility parameters (the turbulent Mach number and the gradient Mach number). Application of the model on compressible homogeneous shear flow by considering various initial conditions shows reasonable agreement with the DNS results of Sarkar. The ability of the models to predict the equilibrium states for the flow in cases A1 and A4 from DNS results of Sarkar is examined, the results appear to be very encouraging.Thus, both parameters Mt and Mg should be used to model significant structural compressibility effects at high-speed shear flow.

To investigate the impact characteristics of oblique flow on dolphin-type pier structures in mountainous river confluence hubs, the Madao Hub of the Pinglu Canal—a pivotal component of China's Western Land-Sea New Corridor initiative—was examined in this study. Full-scale three-dimensional fluid–structure interaction (FSI) simulations were implemented, with validation against physical model experimental data. The flow characteristics and hydrodynamic pressure distributions around ship-berthing piers impacted by the tailwater flow from the Madao Hub were analyzed. Simulation results of the FSIs were benchmarked against standard empirical formulas. The results revealed that under the project's layout configuration, high-velocity flow propagated predominantly along the left bank, primarily impacting piers 8–10. The maximum positive pressure zone was located near the upstream corner of the most-affected berthing pier. As the flow traversed the pier’s leading edge and impinged upon the sidewalls, the hydrodynamic pressure progressively attenuated, transitioning to negative values at the downstream end of the front face and upstream end of the side face. Comparisons indicated that the predicted values matched well with AS500 and IRS standards, whereas IRC 6 standard underestimated the hydrodynamic forces by 85%–90%. Therefore, the IRC 6 standard requires calibration to enhance its safety factor. This study elucidated the pressure distributions around piers under oblique flow conditions, providing a scientific foundation for structural layout optimization, pier geometry selection, and force analysis of piers near mountain river confluences.