scholarly journals Determination of the Surface Roughness Parameter and Wind Shear Exponent of Kisii Region from the On-Site Measurement of Wind Profiles

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Ongaki N. Laban ◽  
Christopher M. Maghanga ◽  
Kerongo Joash
Keyword(s):  
Surface Roughness ◽  
Wind Shear ◽  
Roughness Parameter ◽  
Surface Roughness Parameter ◽  
Wind Speeds ◽  
Display Board ◽  
Mean Wind Speed ◽  
Wind Profiles ◽  
Monthly Variations

The research sought to investigate the surface roughness parameter (Zo) and wind shear exponent (α) of Kisii region (elevation 1710m above sea level, 0.68°S, 34.79°E). A six-month experiment was set at three sites of Kisii region. Two PRO AcuRite 01036 Wireless Weather Stations with pro+ 5-in-1 Sensors were placed at different hub heights above the ground and data were sent and received by a display board set at a room through remote sensing at an interval of 12 minutes. Data was collected from the display board through the pc connect software, grouped into discrete data and then calculated to represent mean wind speed, diurnal variation, daily variation, and monthly variations. The calculated averages of wind speeds at hub heights of 10m and 13m were then used to determine the wind shear exponent and surface roughness parameter of the sites. The wind shear exponents were found to be 0.92, 0.41, and 0.54 for Nyamecheo, Kisii University, and Ikobe stations, respectively, with an average of 0.64. The roughness parameter was also calculated and found to be 3.75, 1.32, and 1.96 for Nyamecheo, Kisii University (KSU), and Ikobe, respectively, with an average of 2.35.

scholarly journals DETERMINATION OF SURFACE ROUGHNESS PARAMETER THROUGH AERIAL IMAGES IN WIND POWER PLANT INSTALLATION

2020 ◽  
Vol 5 (12) ◽  
pp. 66-76
Author(s):  
Ümit Çiğdem Turhal ◽  
Vahab Neccaroğlu
Keyword(s):  
Surface Roughness ◽  
Power Plant ◽  
Lower Cost ◽  
Roughness Parameter ◽  
Aerial Images ◽  
Surface Roughness Parameter ◽  
Roughness Elements ◽  
Time Requirements ◽  
Processing Techniques

The surface roughness parameter is an important parameter in the installation of a wind energy power plant and it varies depending on the dimensions and the distribution of the roughness elements on the land. Before the installation roughness maps indicate roughness of the surface has to be drawn. In today's applications, these maps are drawn approximately by WAsP software using the information obtained from the terrestrial observations belongs to experts. But this application is costly and time consuming and the assessment is based on limited land observations. In this study the surface roughness parameter is determined by digital image processing techniques from the digital images taken over aerial field. Thus it gives the opportunity to consider whole power plant surface into account with lower cost and time requirements over the traditional methods. Images used in the study are obtained from the Map General Command and MATLAB software platform is used. The study is based on the determination of the closure rates on the land by image segmentation method such as OTSU algorithm, fuzzy c-means and k-means algorithms. In order to evaluate the consistency of the results images are evaluated with ERDAS software. Obtained results showed the effectiveness of the study.

Surface Roughness at Wire Electrical Discharge Machining

2015 ◽  
Vol 760 ◽  
pp. 551-556 ◽  
Author(s):  
Oana Dodun ◽  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Vasile Merticaru ◽  
Gheorghe Nagîţ
Keyword(s):  
Surface Roughness ◽  
Empirical Model ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Roughness Parameter ◽  
Wire Electrical Discharge Machining ◽  
Power Type ◽  
Surface Roughness Parameter ◽  
Pulse On Time ◽  
Pulse Off Time

Wire electrical discharge machining is a machining method by which parts having various contours could be detached from plate workpieces. The method uses the electrical discharges developed between the workpiece and the wire tool electrode found in an axial motion, when in the work zone a dielectric fluid is recirculated. In order to highlight the influence exerted by some input process factors on the surface roughness parameter Ra in case of a workpiece made of an alloyed steel, a factorial experiment with six independent variables at two variation levels was designed and materialized. As input factors, one used the workpiece thickness, pulse on time, pulse off-time, wire axial tensile force, current intensity average amplitude defined by setting button position and travelling wire electrode speed. By mathematical processing of the experimental results, empirical models were established. Om the base of a power type empirical model, graphical representations aiming to highlight the influence of some input factors on the surface roughness parameter Ra were achieved. The power type empirical model facilitated establishing of order of factors able to exert influence on the surface roughness parameter Ra at wire electrical discharge machining.

scholarly journals Coastal Boundary Layer Characteristics of Wind, Turbulence, and Surface Roughness Parameter over the Thumba Equatorial Rocket Launching Station, India

2014 ◽  
Vol 2014 ◽  
pp. 1-21 ◽  
Author(s):  
K. V. S. Namboodiri ◽  
Dileep Puthillam Krishnan ◽  
Rahul Karunakaran Nileshwar ◽  
Koshy Mammen ◽  
Nadimpally Kiran kumar
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Wind Direction ◽  
Roughness Parameter ◽  
Turbulent Heat ◽  
Surface Roughness Parameter ◽  
South West Monsoon ◽  
Wind Turbulence ◽  
Coastal Boundary Layer ◽  
Coastal Boundary

The study discusses the features of wind, turbulence, and surface roughness parameter over the coastal boundary layer of the Peninsular Indian Station, Thumba Equatorial Rocket Launching Station (TERLS). Every 5 min measurements from an ultrasonic anemometer at 3.3 m agl from May 2007 to December 2012 are used for this work. Symmetries in mesoscale turbulence, stress off-wind angle computations, structure of scalar wind, resultant wind direction, momentum flux (M), Obukhov length (L), frictional velocity (u*), w-component, turbulent heat flux (H), drag coefficient (CD), turbulent intensities, standard deviation of wind directions (σθ), wind steadiness factor-σθ relationship, bivariate normal distribution (BND) wind model, surface roughness parameter (z0), z0 and wind direction (θ) relationship, and variation of z0 with the Indian South West monsoon activity are discussed.

Considerations Regarding Some Surface State Parameters Characterized by a more Restricted Use

2015 ◽  
Vol 809-810 ◽  
pp. 93-98
Author(s):  
Ionuţ Urzică ◽  
Ciprian Râznic ◽  
Mihai Apostol ◽  
Corina Mihaela Pavăl ◽  
Mihai Boca ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Roughness Parameter ◽  
Cutting Speed ◽  
Roughness Parameters ◽  
Turning Process ◽  
Nose Radius ◽  
Machined Surface ◽  
Surface Roughness Parameter ◽  
Surface Roughness Parameters ◽  
Restricted Use

Frequently, on the drawings of mechanical parts, only indications concerning the surface roughness parameter Ra and, relatively rarely, the surface roughness parameter Rz are included. However, the study of the machined surface roughness highlights the necessity to use yet other surface roughness parameters, in order to have a clearer image on the state of the machined surface. Some other surface roughness parameters possible to be used and presenting importance, without the parameters Ra and Rz, were highlighted. One took into consideration the possibility of measuring parameters Rsk and Rmr by means of the available surface roughness testers. Experimental researches of turning by applying the method of full factorial experiment were developed. As input factors in turning process, the cutting speed, the feed rate and the tool nose radius were used. The experimental results were mathematically processed, being determined empirical mathematical models that highlight the influence of certain input factors of turning process on the values of some surface roughness parameters characterized by a more restricted use

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