On the selection of boundary conditions as applied to smooth surface cylinder scatterers

2002 ◽  
Author(s):  
F.W. Forest ◽  
J.E. Richie
Keyword(s):  
Boundary Conditions ◽  
Smooth Surface ◽  
Selection Of

scholarly journals An Application Of The Theory Of Scale Of Banach Spaces

2015 ◽  
Vol 29 (1) ◽  
pp. 51-59
Author(s):  
Łukasz Dawidowski
Keyword(s):  
Banach Space ◽  
Cauchy Problem ◽  
Boundary Conditions ◽  
Heat Equation ◽  
Banach Spaces ◽  
Abstract Cauchy Problem ◽  
Initial Boundary ◽  
Scale Of Banach Spaces ◽  
The Cauchy Problem ◽  
Selection Of

AbstractThe abstract Cauchy problem on scales of Banach space was considered by many authors. The goal of this paper is to show that the choice of the space on scale is significant. We prove a theorem that the selection of the spaces in which the Cauchy problem ut − Δu = u|u|s with initial–boundary conditions is considered has an influence on the selection of index s. For the Cauchy problem connected with the heat equation we will study how the change of the base space influents the regularity of the solutions.

scholarly journals Selection of screw characteristics and operational boundary conditions to facilitate post-flush urine and faeces separation within single household sanitation systems

2016 ◽  
Vol 2 (6) ◽  
pp. 953-964 ◽  
Author(s):  
E. Mercer ◽  
P. Cruddas ◽  
L. Williams ◽  
A. Kolios ◽  
A. Parker ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
System P ◽  
Sanitation Systems ◽  
Fresh Urine ◽  
Selection Of

This article demonstrates the application of a screw auger to separate fresh urine and faeces in a household scale sanitation system.

Calculation of Optimal Surface Roughness With Respect to Lift/Drag Forces Acting on Wind Turbine Blade

2014 ◽  
Author(s):  
Xuerui Mao ◽  
Simon Hogg
Keyword(s):  
Surface Roughness ◽  
Boundary Conditions ◽  
Smooth Surface ◽  
Adjoint Equation ◽  
Turbine Blades ◽  
Leading Edge ◽  
Sensitivity Study ◽  
Small Magnitude ◽  
Viscous Forces ◽  
Drag Forces

Roughness on the surface of turbine blades induced by icing, dirt, erosion or manufacturing imperfections changes the aerodynamic configurations of wind turbines and reduces the power generation efficiency. In this work, a modified NACA0024 aerofoil is adopted to study effects of surface roughness on lift/drag forces. Three Reynolds numbers, 1000, 2000 and 5000 and a range of angles of attack [0°,20°] are studied. Since the magnitude of the roughness is small, it can be modelled as non-zero velocity boundary conditions imposed on the smooth surface without roughness. The flow with surface roughness can be therefore decomposed as the sum of a flow without roughness and a flow induced by roughness (or the velocity boundary conditions). The first flow can be obtained by solving the Navier-Stokes (NS) equation while the second one is governed by the linearized NS equation. Correspondingly the lift and drag forces acting on the aerofoil can be also decomposed as the sum of a force without considering roughness and a force induced by roughness. Instead of studying a particular type or distribution of roughness, we calculate the optimal roughness, which changes aerodynamic forces most effectively. This optimal roughness is obtained through a sensitivity study by solving an adjoint equation of the linearized NS equation. It is found that the optimal roughness with respect to both drag and lift forces is concentrated around the trailing edge and upper leading edge of the aerofoil and the lift is much more sensitive to roughness than the drag. Then the optimal roughness with a small magnitude is added to the smooth aerofoil geometry and this new geometry is tested through direct numerical simulations (DNS). It is found that the optimal roughness with a small magnitude (e-norm, defined as the square integration of the roughness around the surface, 0.001) induces over 10% change of the lift. Comparing the forces acting on the smooth surface and on the rough surface, it is noticed that the roughness changes the pressure force significantly while has little influence on the viscous forces. The pressure distribution is further inspected to study mechanisms of the effects of roughness on forces.

scholarly journals On the selection of boundary conditions for top tensioned risers facing wave induced vibrations

2018 ◽  
Vol 20 (4) ◽  
pp. 1579-1587
Author(s):  
Mohammad Javad Ketabdari ◽  
Zohreh Sadat Haghayeghi
Keyword(s):  
Boundary Conditions ◽  
Wave Induced ◽  
Selection Of

scholarly journals Selection of Tempoyak Lactic Acid Bacteria As Candidate Strain for Yoghurt Starter Culture

2019 ◽  
Vol 11 (1) ◽  
pp. 39-46
Author(s):  
Hanum Mukti Rahayu ◽  
Mahwar Qurbaniah
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Smooth Surface ◽  
Starter Culture ◽  
Round Shape ◽  
Activity Test ◽  
Acid Producing Bacteria ◽  
Selection Of ◽  
Candidate Strain

Selection of bacteria in yoghurt fermentation is important to produce yoghurt with good quality. Tempoyak lactic acid bacteria is potential to be yoghurt starter culture becouse tempoyak fermentation has similarities in producing lactic acid such as yoghurt. This study aimed to isolate and identify the lactic acid bacteria (LAB) from tempoyak which will be used as a yoghurt starter culture. The methods used in this study included isolation and selection of acid-producing bacteria, lactase and protease activity test, identification of morphology and biochemistry as well as testing the quality of the yoghurt. The results of the study obtained 32 isolates of the LAB with the same characteristic colony, include the round shape, cream-coloured with convex elevation and, smooth surface and entire edge. Selection of acid-producing bacteria obtained 12 isolates with the ability to produce clear zones on MRSA + CaCO3 media ≥ 0.7 cm. Selection of lactase-producing LAB obtained six strains and the protease test obtained two superior strains. Two superior strains namely Tp 12 and Tp 28 have characteristics of coccus, gram-positive, negative catalase, non-endospore and non-motile forms. The organoleptic and several quality tests showed yoghurt using Tp 12 as starter has higher acceptability, the highest levels of lactic acid and lactose levels with values respectively 4.25, 0.84% and 24.53%. This study obtained the LAB strain which can be used as yoghurt starter culture. Tp 12 strain can be used to improve the quality of yoghurt and become a commercial starter that can be applied to various fermented products.

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