Numerical Analysis of Regular and Irregular Surface Roughness in a Microchannel Using LBM

2020 ◽  
pp. 103-115
Author(s):  
M. A. Taher ◽  
M. K. Dey ◽  
Yeonwon Lee
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Irregular Surface

scholarly journals Numerical analysis of the bucket surface roughness effects in Pelton turbine

2013 ◽  
Vol 52 (5) ◽  
pp. 052032 ◽  
Author(s):  
Y X Xiao ◽  
C J Zeng ◽  
J Zhang ◽  
Z G Yan ◽  
Z W Wang
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Roughness Effects ◽  
Pelton Turbine

Numerical analysis of the radiation losses due to surface roughness in integrated optics devices

1996 ◽  
Vol 8 (9) ◽  
pp. 1202-1204 ◽  
Author(s):  
G.H. Jin ◽  
J. Harari ◽  
L. Joannes ◽  
J.P. Vilcot ◽  
D. Decoster
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Integrated Optics ◽  
Integrated Optics Devices ◽  
Radiation Losses

Turbulent Flow over Low-Order Models of Highly Irregular Surface Roughness

AIAA Journal ◽  
2009 ◽  
Vol 47 (5) ◽  
pp. 1288-1299 ◽  
Author(s):  
B. E. Johnson ◽  
K. T. Christensen
Keyword(s):  
Surface Roughness ◽  
Turbulent Flow ◽  
Irregular Surface ◽  
Low Order

Numerical Simulation of Elastohydrodynamically Lubricated Contacts With Rough Surfaces

1994 ◽  
Vol 47 (6S) ◽  
pp. S221-S227 ◽  
Author(s):  
Alan Xiaolan Ai ◽  
Herbert S. Cheng
Keyword(s):  
Numerical Simulation ◽  
Surface Roughness ◽  
Numerical Analysis ◽  
Convective Flow ◽  
Multigrid Method ◽  
Rough Surfaces ◽  
Point Contacts ◽  
Random Roughness ◽  
Lubricated Contacts ◽  
Lubricant Flow

Transient numerical analysis to elastohydrodynamically lubricated point contacts with rough surfaces is described. The numerical simulation is based on the multigrid method. Three types of surface roughness: single dent or bump, oblique waviness and random roughness are reviewed. Under heavily loaded conditions, results reveal a strong domination of Couette flow (convective flow). The presence of sliding greatly increases pressure fluctuation and as a consequence may lead to surface-initiated spallings. For obliquely orientated roughness, lubricant flow intends to deform the ridges and create primarily longitudinal passages.

Effects of implant surface roughness and stiffness of grafted bone on an immediately loaded maxillary implant: a 3D numerical analysis

2008 ◽  
Vol 35 (4) ◽  
pp. 283-290 ◽  
Author(s):  
H.-L. HUANG ◽  
L.-J. FUH ◽  
J.-T. HSU ◽  
M.-G. TU ◽  
Y.-W. SHEN ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Implant Surface

Effect of housing surface roughness on the performance of a centrifugal compressor for turbocharger: Experimental and numerical study

2021 ◽  
pp. 146808742110475
Author(s):  
Ealumalai Karunakaran ◽  
Sanket Mulye ◽  
Jawali Maharudrappa Mallikarjuna
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Numerical Study ◽  
Experimental Results ◽  
Wall Turbulence ◽  
Low Flow ◽  
Pressure Losses ◽  
Compressor Performance

Centrifugal compressor plays a vital role in the performance of a turbocharger. The compressor contains an impeller and housing, including the vaneless diffuser and a volute. The high-speed flow from the impeller is diffused in the diffuser and volute, before being delivered to the engine. Hence, the housing flow characteristics affect the compressor performance and operating range. Generally, housing has noticeable surface roughness, especially in the volute. This study evaluates the effect of the volute surface roughness on the compressor performance by experimental and numerical analysis. The experiments are conducted for three different volute surface roughness levels to measure the overall compressor pressure ratio and efficiency. The uncertainty in the efficiency for experimental results is within ±0.5% pts. Also, steady-state numerical simulations are performed to analyse the flow mechanisms causing pressure losses. Then, a numerical analysis is done to understand the effect of roughness of the diffuser hub and shroud walls on the compressor performance. From the experimental results, it is found that the increase in the roughness level of the volute from the smooth surface by circa 900% and 1400% shows a significant reduction in the compressor efficiency at the design speed (N) and off-design speeds (0.87 and 1.13 N). The reductions of efficiency are about 0.5%–1% pts at the near surge point, 1%–1.5% pts at the peak efficiency point and 2%–2.5% pts at the near choke flow point. The CFD analyses show significantly higher near-wall turbulence and wall shear resulting in additional pressure losses. Also, it is found that the pressure losses are more sensitive to roughness of the diffuser shroud-wall than that of the hub-wall. On the other hand, the diffuser hub-wall roughness increases the radial momentum in the diffuser passage which suppress the flow separation at low flow rates.

Numerical analysis of the correlation between the pitting severity and surface roughness of corroded specimens

2022 ◽  
pp. 1-16
Author(s):  
Firman A. Nugroho ◽  
Wadhah Garhuom ◽  
Gyde Andresen-Paulsen ◽  
Sören Ehlers
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis

NiO Development on FeCrAl Substrate for Catalytic Converter Using Ultrasonic and Nickel Electroplating Methods

2010 ◽  
Vol 129-131 ◽  
pp. 1262-1266 ◽  
Author(s):  
Darwin Sebayang ◽  
Putrasari Yanuandri ◽  
Sulaiman B. Hasan ◽  
Pudji Untoro
Keyword(s):  
Surface Roughness ◽  
Surface Area ◽  
Catalytic Converter ◽  
Ultrasonic Method ◽  
High Surface ◽  
High Surface Area ◽  
Irregular Surface ◽  
Cross Sectional ◽  
Nickel Electroplating ◽  
Area Development

The irregular surface roughness morphology due to ultrasonic method was used approach for increasing the high surface area of substrate and catalyst. The purpose of this paper is to show the ultrasonic and nickel electroplating methods for NiO automotive catalyst development on FeCrAl substrate. The process began with pretreatment of FeCrAl using SiC and/or Al2O3 solution agitating by ultrasonic and followed with nickel electroplating. The oxidation test was conducted for developing the NiO. The physical morphology structure of the presence NiO on the FeCrAl substrate was analyzed using scanning electron microscope (SEM) in combination with energy dispersive X-ray spectroscopy (EDS). The cross sectional observation show the NiO catalyst completely existed on the FeCrAl. The ultrasonic method increases the irregular surface roughness morphology on FeCrAl substrate that influenced the homogeneous and stability of nickel electroplating and NiO surface area development.

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