An experimental study was undertaken to investigate the effects of roughness on structure turbulent boundary layers in open channels. The carried out using a laser Doppler anemometer shallow flows for three different types rough surface, as well hydraulically smooth surface. flow Reynolds number based layer momentum thickness ranged from 1400 4000. comparable with depth and turbulence intensity channel varied 2 4 percent. defect profile correlated an approach which allowed both skin friction...

Abstract A finite volume model was developed to simulate transient heat transfer in firefighters' protective clothing during flash fire exposure. The domain consists of three layers fire-resistant fabrics (outer shell, moisture barrier, and thermal liner) with two air gaps between the layers, human skin, gap skin. accounts for combined conduction-radiation entrapped variation properties energy content both exposure cool down periods accounted for. Predictions were obtained temperature flux...

The flow around a surface-mounted cube has been investigated for decades, yet the fundamentals of mean have not updated to reflect latest advances regarding finite-height square prisms in general. One main gaps is field very near walls, especially sides, and its relationship wake. To investigate these features, large-eddy simulations were carried out at Reynolds number Re =1×104. Two boundary layers considered: thin laminar layer thick turbulent one, provide an overview contrasting layers....

A finite volume model was developed to simulate the transient heat transfer in a protective clothing system. The domain consists of fire-resistant fabric, human skin, and air gap between fabric skin. uses more sophisticated treatment compared previous models: it accounts for combined conduction-radiation within includes variation properties with temperature. Predictions were obtained temperature flux distributions as function time, well time receive skin burn injuries. numerical used explore...

In this paper, a dynamic subgrid scale (SGS) stress model based on Speziale’s quadratic nonlinear constitutive relation [C. G. Speziale, J. Fluid Mech. 178, 459 (1987); T. B. Gatski and C. 254, 59 (1993)] is proposed, which includes the conventional SGS as its first-order approximation. The closure method utilizes both symmetric antisymmetric parts of resolved velocity gradient, allows for anisotropic representation tensor. Unlike Smagorinsky type modeling approaches, proposed does not...

Flip-chip underfill process is a very important step in the flip-chip packaging technology because of its great impact on reliability electronic devices. In this technology, used to redistribute thermo-mechanical stress generated from mismatch coefficient thermal expansion between silicon die and organic substrate for increasing packaging. article, models which have been describe properties flow driven by capillary action are discussed. The included apply Newtonian non-Newtonian behavior...

In this paper, an experimental investigation of the turbulence characteristics a plane wall jet over smooth and rough surfaces, using laser Doppler anemometry (LDA), is reported. The Reynolds number based on slot height exit velocity was approximately Re = 7500. A 36-grit sheet used as surface, creating transitionally flow regime (44<ks+<70). Both inner outer scales were to analyze effects surface roughness stress profiles. Comparisons between present results other LDA hot-wire...

Mathematical and numerical modelling of the tissue culture process in a perfusion bioreactor is able to provide insight into fluid flow, nutrients wastes transport, dynamics pH value, cell growth rate. Knowing complicated interdependence these processes essential for optimizing growth. This paper presents resolved scale simulation, which allows one not only characterize supply glucose inside porous scaffold bioreactor, but also assess overall condition predict The simulation uses simplified...

This article describes an analytical model for the prediction of underfill flow characteristics in a flip-chip package driven by capillary action. In this model, we consider non-Newtonian fluid properties encapsulant as opposed to most other studies where Newtonian were assumed flow. The power-law constitutive equation was applied our study. simulation based on agreed well with measurement obtained from experiments available literature. It further shown that performs better than Washburn...

In this paper, highly disturbed turbulent flows confined within a square duct with uniformly spaced V-shaped ribs mounted on one wall are investigated using large-eddy simulation (LES). Two (60° and 45°) rib cases studied in comparison the perpendicular (90°) case. The LES results validated against set of water-channel measurement data newly acquired by authors. effects different shaped flow systematically terms mean velocity field, turbulence statistics, coherent structures. show that...

This study applies the spectral proper orthogonal decomposition (SPOD) to analyze spatio-temporal characteristics associated with flow fields of a bubbling fluidized bed. The results suggest there is no singular dominant frequency linked highest energy levels; rather, spectrum frequencies. These frequencies are consistent natural from published correlations. SPOD analysis allows for capture quasi-periodicity that arises semi-periodic evolution bubbles in bed and reveals presence multiple...

It is well known that the hydrodynamics of dense gas–particle flows depends heavily on inter-particle and particle–wall collisions; however, subtleties these interactions are not always fully recognized or appreciated. In this study, two-fluid model used to systematically examine effects collision parameters, i.e., particle–particle restitution coefficient, wall specularity simulations a pseudo two-dimensional bubbling fluidized bed. The utilization high-resolution Eulerian facilitates...