A numerical study on wind dams: A novel approach to enhance wind potential using natural barriers

2020 ◽  
Vol 205 ◽  
pp. 112454 ◽  
Author(s):  
M. Anbarsooz
Keyword(s):  
Numerical Study ◽  
Novel Approach ◽  
Wind Potential ◽  
Natural Barriers

scholarly journals Numerical study of magnetic particles mixing in waste water under an external magnetic field

2020 ◽  
Vol 69 (3) ◽  
pp. 266-275 ◽  
Author(s):  
Christos Liosis ◽  
Evangelos G. Karvelas ◽  
Theodoros Karakasidis ◽  
Ioannis E. Sarris
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Numerical Study ◽  
Low Frequency ◽  
Water And Wastewater Treatment ◽  
Novel Approach ◽  
Optimal Value ◽  
Frequency Optimum ◽  
Combined Action ◽  
Aligned Magnetic Field

Abstract The combination of nanotechnology and microfluidics may offer an effective water and wastewater treatment. A novel approach combines the use of magnetic particles which can capture heavy metal impurities in microfluidic ducts. The purpose of this study is to investigate the mixing mechanism of two water streams, one with magnetic particles and the other with wastewater. The optimum mixing is obtained when particles are uniformly distributed along the volume of water in the duct for the combined action of a permanent, spatially and temporally aligned magnetic field. Results showed that mixing is enhanced as the frequency of the magnetic field decreases or its amplitude increases, while magnetic gradient is found to play an insignificant role in the present configuration. Moreover, for simulations with low frequency, the mean concentration of particles is found to be twice as high as compared to the cases with higher frequency. Optimum distribution of particles inside the micromixer is observed for the combination of 0.6 T, 8 T/m and 5 Hz for the magnetic magnitude, gradient and frequency, respectively, where concentration reaches the optimal value of 0.77 mg/mL along the volume of the duct.

scholarly journals MODAL TRIGGERED NONLINEARITIES FOR DAMAGE LOCALIZATION IN THIN WALLED FRC STRUCTURES – A NUMERICAL STUDY

2016 ◽  
Vol 14 (1) ◽  
pp. 21 ◽  
Author(s):  
Tobias Rademacher ◽  
Manfred Zehn
Keyword(s):  
Numerical Study ◽  
Fem Simulation ◽  
Harmonic Distortion ◽  
Mode Shapes ◽  
Novel Approach ◽  
Simulation Based ◽  
Novel Method ◽  
Thin Walled ◽  
Modal Description ◽  
Nonlinear Measure

This paper presents a novel method for detecting locations of damages in thin walled structural components made of fiber reinforced composites (FRC). Therefore, the change of harmonic distortion, which is found by current research to be very sensitive to delamination, under resonant excitation will be derived from FEM-simulation. Based on the linear modal description of the undamaged structure and the damage-induced nonlinearities represented by a nonlinear measure, two spatial damage indexes have been formulated.The main advantage of this novel approach is that the information about the defect is represented mainly by changes in the modal harmonic distortion (MHD), which just needs to be measured in one (or few) structural points. The spatial resolution is given by the pairwise coupling of the MHD with the corresponding mode shapes.

scholarly journals Numerical Study of Circularly Slotted Highly Sensitive Plasmonic Biosensor: A Novel Approach

2020 ◽  
Vol 17 ◽  
pp. 103130 ◽  
Author(s):  
Md. Nazmus Sakib ◽  
S.M. Riazul Islam ◽  
T.V. Mahendiran ◽  
Lway Faisal Abdulrazak ◽  
Md. Shofiqul Islam ◽  
...  
Keyword(s):  
Numerical Study ◽  
Novel Approach ◽  
Highly Sensitive

A numerical study on drag reduction of underwater vehicles using hydrophobic surfaces

2017 ◽  
Vol 233 (1) ◽  
pp. 301-309 ◽  
Author(s):  
Morteza Anbarsooz
Keyword(s):  
Skin Friction ◽  
Numerical Study ◽  
Slip Flow ◽  
Numerical Procedure ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Flow Profile ◽  
Friction Drag ◽  
Hydrophobic Surfaces ◽  
Novel Approach

During last decades, many investigations have been done to find suitable solutions to reduce the drag force of underwater vehicles. These attempts can be divided into two main categories: supercavitating vehicles and unseparated flow patterns. In this study, a novel approach is introduced which uses hydrophobic surfaces for an underwater vehicle with an unseparated flow body profile. Fluid slippage on hydrophobic walls can lead to a considerable reduction of skin friction drag. The effectiveness of this approach for underwater hulls has been examined numerically. In this regard, first, the numerical procedure is validated by comparing the numerical results for the slip flow over a micron-sized spherical particle with the analytical results available in the literature. Next, numerical simulations are performed for an unseparated flow profile at various values of the sliding coefficients. Results show that the principal drag of such profiles is the skin friction drag which can be drastically reduced using hydrophobic surfaces. For the sliding coefficients smaller than 10, the drag coefficient of the underwater vehicle with an unseparated flow profile can be even lower than that of a supercavitating hull.

scholarly journals Offshore Wind Potential of West Central Taiwan: A Case Study

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3702
Author(s):  
Wen-Ko Hsu ◽  
Chung-Kee Yeh
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Power Loss ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Distribution Analysis ◽  
Novel Approach ◽  
Wind Potential ◽  
Mean Wind Speed ◽  
Central Taiwan

In this study, we present the wind distributions from a long-term offshore met mast and a novel approach based on the measure–correlate–predict (MCP) method from short-term onshore-wind-turbine data. The annual energy production (AEP) and capacity factors (CFs) of one onshore and four offshore wind-turbine generators (WTG) available on the market are evaluated on the basis of wind-distribution analysis from both the real met mast and the MCP method. Here, we also consider the power loss from a 4-month light detection and ranging (LiDAR) power-curve test on an onshore turbine to enhance the accuracy of further AEP and CF evaluations. The achieved Weibull distributions could efficiently represent the probability distribution of wind-speed variation, mean wind speed (MWS), and both the scale and shape parameters of Weibull distribution in Taiwan sites. The power-loss effect is also considered when calculating the AEPs and CFs of different WTGs. Successful offshore wind development requires (1) quick, accurate, and economical harnessing of a wind resource and (2) selection of the most suitable and efficient turbine for a specific offshore site.

scholarly journals Blind disturbance separation and identification in a transitional boundary layer using minimal sensing

2021 ◽  
Vol 927 ◽  
Author(s):  
I. Gluzman ◽  
J. Cohen ◽  
Y. Oshman
Keyword(s):  
Boundary Layer ◽  
Numerical Study ◽  
A Priori ◽  
Boundary Layer Transition ◽  
Linear Stability Theory ◽  
Plasma Actuators ◽  
Flow State ◽  
Layer Transition ◽  
Novel Approach ◽  
Tollmien Schlichting

A novel approach is presented for identifying disturbance sources in wall-bounded shear flows. The underlying approach models the flow state, as measured by sensors embedded in the flow, as a mixture of disturbance sources. The degenerate unmixing estimation technique is adopted as a blind source separation technique to recover the separate sources and their unknown mixing process. The efficiency of this approach stems from its ability to isolate any, a priori unknown, number of sources, using two sensors only. Furthermore, by adding a single additional sensor, the method is expanded to also determine the propagation velocity vector of each of the isolated sources, based on sensor readings from three sensors appropriately located in the flow field. Theoretical guidelines for locating the sensors are provided. The power of the method is demonstrated via computer simulations and wind-tunnel experiments. The numerical study considers disturbances comprising discrete Tollmien–Schlichting waves and wave packets. Linear stability theory is used to model source mixtures acquired by sensors placed in a Blasius boundary layer. The experimental study investigates the flow over a flat plate, with hot wires as sensors, and a loudspeaker and plasma actuators as source generators. Based on numerical and experimental demonstrations, it is believed that the new approach should prove useful in various applications, including active control of boundary layer transition from laminar to turbulent flow.

scholarly journals A Numerical Study of Non-hydrostatic Shallow Flows in Open Channels

2017 ◽  
Vol 64 (1) ◽  
pp. 17-35 ◽  
Author(s):  
Yebegaeshet T. Zerihun
Keyword(s):  
Free Surface ◽  
Hydrostatic Pressure ◽  
Flow Field ◽  
Stokes Equations ◽  
Numerical Study ◽  
Free Surface Flows ◽  
Vertical Acceleration ◽  
Novel Approach ◽  
Pressure Profiles ◽  
Turbulent Characteristics

AbstractThe flow field of many practical open channel flow problems, e.g. flow over natural bed forms or hydraulic structures, is characterised by curved streamlines that result in a non-hydrostatic pressure distribution. The essential vertical details of such a flow field need to be accounted for, so as to be able to treat the complex transition between hydrostatic and non-hydrostatic flow regimes. Apparently, the shallow-water equations, which assume a mild longitudinal slope and negligible vertical acceleration, are inappropriate to analyse these types of problems. Besides, most of the current Boussinesq-type models do not consider the effects of turbulence. A novel approach, stemming from the vertical integration of the Reynolds-averaged Navier-Stokes equations, is applied herein to develop a non-hydrostatic model which includes terms accounting for the effective stresses arising from the turbulent characteristics of the flow. The feasibility of the proposed model is examined by simulating flow situations that involve non-hydrostatic pressure and/or nonuniform velocity distributions. The computational results for free-surface and bed pressure profiles exhibit good correlations with experimental data, demonstrating that the present model is capable of simulating the salient features of free-surface flows over sharply-curved overflow structures and rigid-bed dunes.

Hydro-Mechanical Constant-Speed Motion Control Using Shear Thickening Fluid

2017 ◽  
Author(s):  
Mohamad Sleiman ◽  
Karim Hassoun ◽  
Matthias Liermann
Keyword(s):  
Pressure Difference ◽  
Numerical Study ◽  
Shear Thickening ◽  
Control Valve ◽  
Flow Control Valve ◽  
Velocity Control ◽  
Shear Thickening Fluid ◽  
Novel Approach ◽  
Dilatant Fluid ◽  
Low Sensitivity

This paper proposes a novel approach to control the velocity of a piston using dilatant fluid. Commonly, a pressure compensated flow control valve is used for this purpose. It produces excellent results but is mechanically complex. A setup is proposed that makes use of the unique properties of dilatant (i.e. shear thickening) non-Newtonian fluids. A simple tube section filled with dilatant material can be used to achieve very low sensitivity of flow rate vs. pressure difference. A numerical study shows how the power law which relates the fluid shear rate to its viscosity results in this low sensitivity of flow to pressure difference. An experimental setup was build to validate the findings using a cheap and commercially available shear thickening fluid. It was found that the dilatant material used does not have a highly pronounced dilatant property and therefore the sensitivity of flow vs. pressure difference was not as low as desired. Nevertheless, the results support the practical applicability of this novel type of velocity control.

scholarly journals A Novel Approach to Improve Acid Diversion in Carbonate Rocks Using Thermochemical Fluids: Experimental and Numerical Study

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2976 ◽  
Author(s):  
Mustafa Ba Alawi ◽  
Amjed Hassan ◽  
Murtada Saleh Aljawad ◽  
Muhammad Shahzad Kamal ◽  
Mohamed Mahmoud ◽  
...  
Keyword(s):  
Numerical Study ◽  
Analytical Models ◽  
Scale Model ◽  
Low Permeability ◽  
Minor Effect ◽  
Critical Measure ◽  
Novel Approach ◽  
Effective Performance ◽  
Acid Diversion ◽  
Porosity And Permeability

The distribution of acid over all layers of interest is a critical measure of matrix acidizing efficiency. Chemical and mechanical techniques have been widely adapted for enhancing acid diversion. However, it was demonstrated that these often impact the formation with damage after the acid job is completed. This study introduces, for the first time, a novel solution to improve acid diversion using thermochemical fluids. This method involves generating nitrogen gas at the downhole condition, where the generated gas will contribute in diverting the injected acids into low-permeability formations. In this work, both lab-scale numerical and field-scale analytical models were developed to evaluate the performance of the proposed technique. In addition, experimental measurements were carried out in order to demonstrate the application of thermochemical in improving the acid diversion. The results showed that a thermochemical approach has an effective performance in diverting the injected acids into low-permeability rocks. After treatment, continuous wormholes were generated in the high-permeability rocks as well as in low-permeability rocks. The lab-scale model was able to replicate the wormholing impact observed in the lab. In addition, alternating injection of thermochemical and acid fluids reduced the acid volume 3.6 times compared to the single stage of thermochemical injection. Finally, sensitivity analysis indicates that the formation porosity and permeability have major impacts on the acidizing treatment, while the formations pressures have minor effect on the diversion performance.

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