Mini Sediment Columns and Two-Dimensional Sediment Flow-Through Microcosms: Versatile Experimental Systems for Studying Biodegradation of Organic Contaminants in Groundwater Ecosystems

Author(s):  
Roland Hofmann ◽  
Michael Grösbacher ◽  
Christian Griebler
1960 ◽  
Vol 82 (4) ◽  
pp. 921-927 ◽  
Author(s):  
Friedrich O. Ringleb

The conditions for the equilibrium of two vortexes in a two-dimensional flow through a duct or diffuser are derived. Potential-flow considerations and a few basic results from viscous-flow theory are used for the discussion of the role of cusps as separation control and trapping devices for standing vortexes. The investigations are applied to cusp diffusers especially with regard to the wind tunnel of the James Forrestal Research Center of Princeton University.


In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).


A class of two-dimensional channels, with walls whose radius of curvature is uniformly large relative to local channel width, is described, and the velocity field of laminar flow through these channels is obtained as a power series in the small curvature parameter. The leading term is the Jeffery-Hamel solution considered in part I, and it is shown here how the higher-order terms are found. Terms of the third approximation have been computed. The theory is applied to two examples, for one of which experimental results are available and confirm the theoretical values with fair accuracy.


Author(s):  
M. Yasep Setiawan ◽  
Wawan Purwanto ◽  
Wanda Afnison ◽  
Nuzul Hidayat

This study discusses the numerical study of two-dimensional analysis of flow through circular cylinders. The original physical information entered in the equation governing most of the modeling is transferred into a numerical solution. Fluid flow on two-dimensional circular cylinder wall using high Reynolds k-ε modeling (Re = 106), Here we will do 3 modeling first oder upwind, second order upwind and third order MUSCL by using k-ε standard.  The general procedure for this research is formulated in detail for allocations in the dynamic analysis of fluid computing. The results of this study suggest that MUSCL's third order modeling gives more accurate results better than other models.


Author(s):  
Fedor V. PELEVIN ◽  
Aleksey V. PONOMAREV

The paper discusses a new method for regenerative cooling of the chamber of liquid-propellant rocket engines using the concept of interchannel coolant flow through a porous metal mesh made by vacuum diffusion welding of woven metal netting. It provides a theoretical rationale for switching from unidimensional (longitudinally channeled) flow to two-dimensional (interchannel) inter-mesh flow coolant through a porous mesh. It provides experimental data for hydraulic resistance and heat exchange in porous metal meshes. Based on the experimental data, a generalized criterial equation was obtained for surface heat release in the paths with interchannel two-dimensional intermesh coolant flow through metal mesh. The paper examines the efficiency of heat exchange in the paths with interchannel coolant flow. Key words: regenerative cooling, interchannel flow; vacuum diffusion technology, metal mesh; hydraulic resistance; heat exchange, heat exchange efficiency.


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