Aquatic plants convert mean kinetic energy into turbulent kinetic energy at the scale of the plant stems and branches. This energy transfer, linked to wake generation, affects vegetative drag and turbulence intensity. Drawing on this physical link, a model is developed to describe the drag, turbulence and diffusion for flow through emergent vegetation which for the first time captures the relevant underlying physics, and covers the natural range of vegetation density and stem Reynolds' numbers. The model is supported by laboratory and field observations. In addition, this work extends the cylinder-based model for vegetative resistance by including the dependence of the drag coefficient, CD, on the stem population density, and introduces the importance of mechanical diffusion in vegetated flows.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1998WR900069

Drag, turbulence, and diffusion in flow through emergent vegetation

Heat transfer and pressure drop correlations for the rectangular offset strip fin compact heat exchanger

It is the objective of this thesis to demonstrate exergy analysis as a powerful instrument to obtain sustainable development. An important aspect of sustainable development is the minimisation of irreversibilities caused by the use of non-renewables. In order to limit the scope of this thesis sustainable development associated with production is considered only. The demonstration cases from practice are selected on four levels: components from process units, process units, complete production processes and, finally, products from production processes. This approach requires life cycle analysis aspects to be included in the exergy analysis.

Thermodynamics and sustainable development; the use of exergy analysis and the reduction of irreversibility

The heat released in the condenser must be rejected to the environment. In regions lacking large bodies of water this rejection must be to the atmosphere. The requirement for a small temperature difference between the exhaust steam and the atmosphere, while rejecting large quantities of heat to air having a low heat capacity compared with water, poses a challenging technological problem which has resulted in a number of different engineering solutions.

/pdf/air-cooled-heat-exchangers-and-cooling-towers-5fcayz4p2h.pdf

Air-cooled heat exchangers and cooling towers

The effects of topology upon fluid-flow and heat-transfer within cellular copper structures

This book is covered under the following headings: Basic {epsilon}-N{sub tu} analysis for complicated flow arrangements; Single-phase heat transfer and pressure drop measurements, correlations and predictions; and Applications of compact heat exchangers.

R.K. Shah

Papers

Compact Heat Exchangers