Angelos N. Findikakis

Bio: Angelos N. Findikakis is an academic researcher from Stanford University. The author has contributed to research in topics: Heat generation & Stratified flow. The author has an hindex of 19, co-authored 42 publications receiving 1857 citations. Previous affiliations of Angelos N. Findikakis include Nanyang Technological University.

Numerical simulation of three‐dimensional flow in a cavity

Abstract: SUMMARY Previous three-dimensional simulations of the lid-driven cavity flow have reproduced only the most general features of the flow. Improvements to a finite difference code, REBUFFS, have made possible the first completely successful simulation of the three-dimensional lid-driven cavity flow. The principal improvement to the code was the incorporation of a modified QUICK scheme, a higher-order upwind finite difference formulation. Results for a cavity flow at a Reynolds number of 3200 have reproduced experimentally observed Taylor-Gortler-like vortices and other three-dimensional effects heretofore not simulated. Experimental results obtained from a unique experimental cavity facility validate the calculated results.

Modeling Leachate Generation and Transport in Solid Waste Landfills

Abstract: Numerous mathematical models have been developed to simulate processes governing leachate occurrence and behaviour in landfills. The emphasis of these models have generally been on estimating leachate quantity and quality in order to control its associated environmental impacts, particularly on ground and surface water pollution, enhance methanogenesis and landfill stabilization, and provide guidance in the design of leachate control, recirculation and collection systems. These models have been successful to a limited extent, more in estimating leachate quantity than its composition, because of inherent uncertainties associated with estimating model parameters that can adequately describe the complex biological, chemical, and physical processes in landfills. They become increasingly useful as more field data are obtained and used for calibration and validation purposes. This paper presents a review of mathematical models designed to simulate leachate generation and transport in municipal solid waste landf...

Numerical Simulation of Gas Flow in Sanitary Landfills

Abstract: The stabilization of refuse placed in sanitary landfills and the quality and rate of production of gases in landfills are principally the result of complex biological processes. A numerical model has been developed for simulating one-dimensional flow of a mixture of methane, carbon dioxide and nitrogen through sanitary landfills. Finite-difference approximations to the differential gas flow equations were derived with an implicit time stepping scheme. The nonlinear finite-difference equations were solved iteratively using the Newton-Raphson method. An explicit formulation was also explored, but the time step size required for stability was prohibitively small. The boundary condition at the landfill-air interface includes the assumption that the total pressure cannot drop below atmospheric pressure within a thin layer at the top of the landfill cover. The model was applied to data from two recent landfills. The pressure and concentration profiles predicted by the model are close to field observations.

Sustainable biochar to mitigate global climate change

Abstract: Production of biochar (the carbon (C)-rich solid formed by pyrolysis of biomass) and its storage in soils have been suggested as a means of abating climate change by sequestering carbon, while simultaneously providing energy and increasing crop yields. Substantial uncertainties exist, however, regarding the impact, capacity and sustainability of biochar at the global level. In this paper we estimate the maximum sustainable technical potential of biochar to mitigate climate change. Annual net emissions of carbon dioxide (CO 2 ), methane and nitrous oxide could be reduced by a maximum of 1.8 Pg CO 2 -C equivalent (CO 2 -C e ) per year (12 % of current anthropogenic CO 2 -C e emissions; 1 Pg = 1 Gt), and total net emissions over the course of a century by 130 Pg CO 2 -C e , without endangering food security, habitat or soil conservation. Biochar has a larger climate-change mitigation potential than combustion of the same sustainably procured biomass for bioenergy, except when fertile soils are amended while coal is the fuel being offset.

Stratocumulus-capped mixed layers derived from a three-dimensional model

Abstract: Results of a three-dimensional numerical model are analysed in a study of turbulence and entrainment within mixed layers containing stratocumulus with or without parameterized cloud-top radiative cooling. The model eliminates most of the assumptions invoked in theories of cloud-capped mixed layers, but suffers disadvantages which include poor resolution and large truncation errors in and above the capping inversion. For relatively thick mixed layers with relatively thick capping inversions, the cloud-top radiative cooling is found to be lodged mostly within the capping inversion when the cooling is confined locally to the upper 50 m or less of the cloud. It does not then contribute substantially towards increased buoyancy flux and turbulence within the well mixed layer just below. The optimal means of correlating the entrainment rate, or mixed-layer growth rate, for mixed layers of variable amounts of stratocumulus is found to be through functional dependence upon an overall jump Richardson number, utilizing as scaling velocity the standard deviation of vertical velocity existing at the top of the mixed layer (near the center of the capping inversion). This velocity is found to be a fraction of the generalized convective velocity for the mixed layer as a whole which is greater for cloud-capped mixed layers than for clear mixed layers.

Advanced Engineering Mathematics. By C. R. Wylie. Pp. xiv, 813. 1966. (McGraw-Hill.)

Abstract: Ordinary differential equations of the first order linear differential equations complex numbers and linear algebra simultaneous linear differential equations numerical methods the descriptive theory of nonlinear differential equations mechanical systems and electric circuits Fourier series Fourier integrals and Fourier transforms the Laplace transformation partial differential equations Bessel functions and Legendre polynomials applications and further properties of matrices vector analysis the calculus of variations analytic functions of a complex variable infinite series in the complex plane the theory of residues conformal mapping.