Development Of Internal Boundary Layer Research Articles

Summer heat environment in surrounding region of urban rivers

Meteorological field observations were conducted at Am-river in summer to evaluate the effect of urban rivers on microclimate of the adjacent city region. The observation in the river course consists of measurements on velocity, temperature and humidity profiles by using captive balloons and measurements on momentum, heat and vapor fluxes performed on flood plain and water body. The development of internal boundary layers on vegetated flood plain and water surface associated with cooling of the atmosphere were observed. The role of flood plain and water body in heat exchanging process are discussed based on the results of the flux measurements.

Discussion of wind -3: Model study of the development of internal boundary layers over urban areas. W. Theurer

Discussion of wind -3: Model study of the development of internal boundary layers over urban areas. W. Theurer

Modeling of Evaporation from Bare Land including advection and ground water flow

For estimation of evaporation rate from large area including a lot of fields which have different characters, for example roughness and wetness, the way how to average evaporation in each fields must be known. In order to estimate the effect of difference of ground surface, the effects of advection and development of internal boundary layer must be investigated.In this paper, a numerical simulation by a two-dimensional model has been undertaken. In this model, the advection in atmosphere and the ground water flow are included. And some results by this simulation model have been given.

Effect of cold-air advection on internal boundary-layer development over warm oceanic currents

Field experiments have shown that an internal boundary layer (IBL) can develop when the wind blows perpendicularly from the cold-water side of a warm oceanic current to the warmer side. The height of this IBL downwind from the thermal front as computed by an equation originally developed by Venkatram is in excellent agreement with observations.

Terrain roughness and atmospheric stability at a typical coastal site

Directional dependence of horizontal wind direction fluctuations (Σθ) is studied at the coastal site of Madras Atomic Power Project, Kalpakkam with significant inhomogeneity in roughness element distribution around the location of measurement. Σθ is measured by a potentiometric wind vane mounted on a 30 m meteorological tower. Values of Σθ showed as high as threefold variation for the same atmospheric stability depending on the effective roughness length of the upwind sector. Average Σθ values separated for sea- and land-breeze conditions, when correlated with Pasquill stability categories showed a monotonic decrease with increasing stability for land breeze but was found to increase for change from D to F category during sea breezes presumably due to the influence of an internal boundary-layer development.

A model of internal boundary-layer development

A slab model of the boundary layer was used to study the dynamics of the internal boundary layer associated with changes in surface temperature. The usual numerical procedure involving finite differences was avoided by solving the governing equations in a Lagrangian framework. The results of the modelling study showed that mixed-layer growth was enhanced by: (a) an increase in surface roughness; (b) an increase in the surface temperature change; and (c) a decrease in the horizontal velocity. It was found that the vertical velocity induced by variations in the horizontal velocity could play an important role in controlling the expansion of the mixed layer. The second part of the study involved the formulation of a model by simplifying the governing equations. The analytical solution obtained from the model compared favourably with the results of the numerical model. Furthermore, the analytical expression for the mixed-layer height was virtually identical to that presented by Raynor et al. (1974) to fit their observational data.

Internal boundary layer development and fumigation

The Tennekes-Carson mixed layer model is used in a Lagrangian framework to predict the development of the internal boundary layer associated with the flow of cold stable air from water onto warmer land. The model yields an analytical expression for the internal boundary layer height as a function of the distance from the land-water boundary. For the special case of small distances from the shoreline the expression reduces to a form which is virtually identical to that of the empirical equation presented by Raynor et al. (1974) to fit their observational data.