Dynamical models, atmospheric flow modelling

Rheological Properties. Rheological studies of the nanocomposites were performed using a Rheometrics Mechanical Spectrometer model 800 on 25mm diameter samples punched from the injection molded plaques. Dynamic oscillatory shear flow measurements of the nanocomposites were made in the linear regime of strain in a frequency range of 0.1 to 100 rad/s under a continuous nitrogen atmosphere. 

Problem. In this example, we consider the flow around a body. Air, at atmospheric pressure, flows at 20 m s 1 across a bank of heat exchanger tubes. A l/10th-scale model is built. At what velocity must air flow over the model bank of tubes to achieve dynamic similarity ... 

Interfacial mass transfer is an important consideration in many dynamic processes involving the transport of a gaseous species across a gas-liquid interface. In particular the rate of trace gas incorporation into aqueous drops in the atmosphere has recently received much attention because of its relevance to acid precipitation (1,2). In the present paper, mass accommodation coefficient measurements are reported for O3 and SO2 on water surfaces, using an UV absorption-stop flow technique. The results are incorporated into a simple model considering the coupled interfacial mass transfer and aqueous chemistry in aqueous drops. Some implications of the measured accommodation coefficients on the oxidation of SO2 by O3 in cloud water are discussed. 

The use of local theories, incorporating parameters such as the eddy viscosity Km and eddy thermal conductivity Ke, has given reasonable descriptions of numerous important flow phenomena, notably large scale atmospheric circulations with small variations in topography and slowly varying surface temperatures. The main reason for this success is that the system dynamics are dominated primarily by inertial effects. In these circumstances it is not necessary that the model precisely describe the role of turbulent momentum and heat transport. By comparison, problems concerned with urban meso-meteorology will be much more sensitive to the assumed mode of the turbulent transport mechanism. The main features of interest for mesoscale calculations involve abrupt... 

Gill AE (1982) Atmosphere - Ocean Dynamics. Academic Press Inc, San Diego Gosman AD, Lekakou C, Polits S, Issa RI, Looney MK (1992) Multidimensional Modeling of Turbulent Two-Phase Flows in Stirred Vessels. AIChE J 38(12) 1946-1956... 

Figure 1 Modular model stmcture of meshing, computer fluid dynamics, air and water quality model. The hydrodynamie and the atmospheric models compute flow, dispersion, and temperature fields for the water and air quality model. All 3 simulations utilize the same horizontal triangle-mesh generated by the unstructured meshing tool.

These estimates are assessed from a hierarchy of models that encompass a simple climate model, several Earth Models of Intermediate Complexity (EMICs) and a large number of Atmosphere Ocean Global Circulation Models (AOGCMs). Excludes future rapid dynamic changes in ice flow. 

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