Temporal mixing-layer

Z3.2.2.2 Diffusion Flame in a Temporal Mixing-Layer Together with HIT, the temporal mixing-layer (TML) is a useful configuration for the numerical study of turbulent flows. The TML configuration can be thought... 

Okong o, N. and J. Bellan, Consistent large-eddy simulation of a temporal mixing layer laden with evaporating drops. Rart 1. Direct numerical simulation, formulation and a priori analysis. J. Fluid Mech., 2004. 499 1-47. 

Zeolite minerals (wairakite, laumontite etc.), mixed-layer clay minerals and sme-cite occur in the upper part of the propylitically altered rocks (e.g., Seigoshi, Fuke, Kushikino), but they are sometimes poor in amounts. Generally carbonates are more abundant in the mine area as in the Toyoha district. Temporal relationship between the formation of high temperature propylitic alteration minerals (epidote, actinolite, prehnite) and low temperature propylitic alteration minerals) (wairakite, laumontite, chlorite/smectite, smectite) in these areas (Seigoshi, Fuke, Kushikino) is uncertain. 

Once these nuclides deposit on the ocean floor they are likely to be subjected to particle mixing processes. In the following we discuss attenuation due to a simple case of mixing, in which the sedimentary particles are mixed to a constant depth, L, from the sediment-water interface [72,73]. For such a case the temporal variation in the standing crop (atoms/cm2) C, of the radionuclide in the mixed layer is given by ... 

Figure 13.20 Temporal variation in CO2 fluxes at three stations in the Hudson River estuary. Positive values represent production of CC and negative values are consumption. CO2 consumption represents the sum of net primary production (NPP) integrated over the photic zone and dark assimilation integrated over the surface mixed layer. Error bars represent 1 standard deviation. (Modified from Taylor et al., 2003.)...

Figure 16.18 Distribution, abundance and temporal dynamics of N2 fixing bacteria at Station ALOHA. (A) Vertical profiles of <10 pm (left) and >10 pm (right) nifH phylotypes in December 2002 relative to upper mixed-layer depth (dashed line) and 1 % surface radiance isopleth (dotted line). Error bars are 1SD of triplicate QPCR (45 cycles) reactions. From Church et al. (2005a).

Further insight into the behavior of the ocean-atmosphere system can be gained by considering a sudden perturbation of atmospheric 14C (Houtermans et al, 1973) and the subsequent adjustment to new steady state conditions. We set G (t) = G -AG and Gj(l) = G -AG where G and G represent the inventories of l4C in the atmosphere and mixed layer, respectively, when the new steady state is reached, and AG and AG are the deviations from these values at time t. The equations governing the temporal change following an input pulse then reduce to... 

The main objective of the analytical work was to check the ability of general-purpose fluid dynamics codes (like FLOW3D [8] or ASTEC [9],(10]) to reproduce (with reasonable accuracy) the overall development of stratified mixing layers at various Prandtl numbers and to provide a code for direct numerical simulation (modification of code FLOW-SB [11]). Particularly important was the participation of ASTEC as well as FLOW3D in different benchmark calculation tasks. The adaptation of the pseudo-spectral code FLOW-SB for the direct numerical simulation (DNS) of stratified mixing layers was very successful. Its ability to calculate the temporal development of flow structures and temperature fields is particularly important, and because of the possibility to visualise these structures, direct comparison with experimental observations (video records) is also feasible. 

A. Cortesi, "Direct Numerical Simulation of a Temporally-Developing, Stably-Stratified Mixing Layer for a Wide Range of Richardson and Prandtl Numbers", ETH-Dissertation, Nr 11699, Zurich 1996. 

For the purpose of direct numerical simulation (DNS), the pseudo-spectral code FLOW-SB (originally developed to study wall turbulence) has been adapted to the temporal (spatially periodic), stratified mixing-layer problem. 

Moresco, P. and Healey, J.J. (2000). Spatio-temporal instability in mixed convection boundary layers, J. Fluid Mech. 402 89-107. 

Theoretical approaches to the prediction of H x,y,t) would involve the solution of the boundary layer equations for coupled energy and momentum transport or, more simply, the solution of the energy equations in conjunction with a constructed wind field. The application of such approaches to the prediction of inversion height has not yet been reported. Now, empirical models offer the only available means to estimate H. For those areas where it is necessary only to account for temporal variations in H, interpolation and extrapolation of measured mixing heights may be sufficient. When it is important to estimate // as a function of x,y, and t, a detailed knowledge of local meteorology is essential. 

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