scholarly journals Numerical Study of a Reconfigurable Multiband Microwave Photonic Filter Using a Tunable Fabry-Perot Filter

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1473
Author(s):  
Blaise Tshibangu-Mbuebue ◽  
Roberto Rojas Laguna ◽  
Min Won Lee ◽  
Jorge Rodríguez-Asomoza ◽  
Ignacio Enrique Zaldívar-Huerta
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Multimode Laser ◽  
Microwave Photonic ◽  
Communications Systems ◽  
Frequency Tunability ◽  
Fabry Perot ◽  
Microwave Photonic Filters ◽  
Simulation Results ◽  
Multimode Laser Diode

Microwave photonic filters (MPFs) with the capabilities of bandwidth reconfigurability and frequency tunability in the GHz range are of great interest in high-speed communications systems. In this paper, we propose a new reconfigurable multiband microwave photonic filter (MPF) using a tunable Fabry–Perot Filter (FPF). It is demonstrated by numerical simulations that the modification of the intermodal separation (δλ) of a multimode laser diode (MLD) by tunable FPF allows for the reconfigurable multi-passband of the MPF. Our simulation results show that our new filter system is promising to communications systems.

Numerical Study on the Effect of Stern Flap for Hydrodynamic Performance of Catamaran

2019 ◽  
Author(s):  
Peng Zhou ◽  
Liwei Liu ◽  
Lixiang Guo ◽  
Qing Wang ◽  
Xianzhou Wang
Keyword(s):  
High Speed ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Experimental Studies ◽  
Hydrodynamic Performance ◽  
Flow Solver ◽  
Calm Water ◽  
Unsteady Simulation ◽  
Ship Hydrodynamic ◽  
Simulation Results

Abstract This paper presents CFD simulation results of the stern flap effect with different lengths for hydrodynamic performance of catamaran moving in calm water, including resistance and sailing attitude. Inhouse viscous CFD (computational fluid dynamics) code HUST-Ship (Hydrodynamic Unsteady Simulation Technology for Ship) is used for the study. The catamaran with/without stern flap with different lengths were studied. The trim and sinkage of the catamaran were solved coupled with flow solver. Experimental studies in calm water were conducted to validate the numerical method. The comparison of hydrodynamic performance of catamaran with stern flaps of different lengths was made. The results show that the stern flap can reduce the sailing attitude and has influence for the resistance of catamaran at high-speed.

scholarly journals Experimental and Numerical Study of Water Entry Supercavity Influenced by Turbulent Drag-Reducing Additives

2014 ◽  
Vol 6 ◽  
pp. 280643 ◽  
Author(s):  
Chen-Xing Jiang ◽  
Feng-Chen Li
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
High Speed ◽  
Numerical Study ◽  
Ccd Camera ◽  
Water Entry ◽  
Multiphase Model ◽  
Turbulent Drag ◽  
Unsteady Rans ◽  
Simulation Results

The configurational and dynamic characteristics of water entry supercavities influenced by turbulent drag-reducing additives were studied through supercavitating projectile approach, experimentally and numerically. The projectile was projected vertically into water and aqueous solution of CTAC with weight concentrations of 100, 500, and 1000 ppm, respectively, using a pneumatic nail gun. The trajectories of the projectile and the supercavity configuration were recorded by a high-speed CCD camera. Besides, water entry supercavities in water and CTAC solution were numerically simulated based on unsteady RANS scheme, together with application of VOF multiphase model. The Cross viscosity model was adopted to represent the fluid property of CTAC solution. It was obtained that the numerical simulation results are in consistence with experimental data. Numerical and experimental results all show that the length and diameter of supercavity in drag-reducing solution are larger than those in water, and the drag coefficient is smaller than that in water; the maintaining time of supercavity is longer in solution as well. The surface tension plays an important role in maintaining the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitation and drag reduction.

Development of the Terahertz Inspection Technology using Multimode Laser Diode

2013 ◽  
Vol 133 (8) ◽  
pp. 430-435 ◽  
Author(s):  
Tohru Takanaka ◽  
Hiroyuki Nishikawa ◽  
Yoshito Sameda ◽  
Keiji Yamamoto
Keyword(s):  
Laser Diode ◽  
Multimode Laser ◽  
Multimode Laser Diode

scholarly journals Development of a Long Period Fiber Grating Interrogation System Using a Multimode Laser Diode

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 749
Author(s):  
Luís Henrique Silva ◽  
Paulo Santos ◽  
Luís C. C. Coelho ◽  
Pedro Jorge ◽  
José Manuel Baptista
Keyword(s):  
Laser Diode ◽  
Measurement Errors ◽  
Laser Scanning ◽  
Fiber Grating ◽  
Light Sources ◽  
Fiber Gratings ◽  
Multimode Laser ◽  
Central Wavelength ◽  
Long Period ◽  
Multimode Laser Diode

Optical fiber gratings have long shown their sensing capabilities. One of the main challenges, however, is the interrogation method applied, since typical systems tend to use broadband light sources with optical spectrum analyzers, laser scanning units or CCD (Charged Coupled Device) spectrometers. The following paper presents the development of an interrogation system, which explores the temperature response of a multimode laser diode, in order to interrogate long period fiber gratings. By performing a spectral sweep along one of its rejection bands, a discrete attenuation spectrum is created. Through a curve fitting technique, the original spectrum is restored. The built unit, while presenting a substantially reduced cost compared with typical interrogation systems, is capable of interrogating along a 10 nm window with measurement errors reaching minimum values as low as 0.4 nm, regarding the grating central wavelength, and 0.4 dB for its attenuation. Given its low cost and reduced dimensions, the developed system shows potential for slow-changing field applications.

Numerical study of the flow over the modified simple frigate shape

2020 ◽  
pp. 095441002097775
Author(s):  
Tong Li ◽  
Yibin Wang ◽  
Ning Zhao
Keyword(s):  
Bluff Body ◽  
Recirculation Zone ◽  
Numerical Study ◽  
Reference Value ◽  
Flow Fields ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Simulation Results

The simple frigate shape (SFS) as defined by The Technical Co-operative Program (TTCP), is a simplified model of the frigate, which helps to investigate the basic flow fields of a frigate. In this paper, the flow fields of the different modified SFS models, consisting of a bluff body superstructure and the deck, were numerically studied. A parametric study was conducted by varying both the superstructure length L and width B to investigate the recirculation zone behind the hangar. The size and the position of the recirculation zones were compared between different models. The numerical simulation results show that the size and the location of the recirculation zone are significantly affected by the superstructure length and width. The results obtained by Reynolds-averaged Navier-Stokes method were also compared well with both the time averaged Improved Delayed Detached-Eddy Simulation results and the experimental data. In addition, by varying the model size and inflow velocity, various flow fields were numerically studied, which indicated that the changing of Reynolds number has tiny effect on the variation of the dimensionless size of the recirculation zone. The results in this study have certain reference value for the design of the frigate superstructure.

scholarly journals Verification of electric steel punching simulation results using microhardness

2021 ◽  
Author(s):  
Sampsa Vili Antero Laakso ◽  
Ugur Aydin ◽  
Peter Krajnik
Keyword(s):  
Plastic Deformation ◽  
High Speed ◽  
Steel Sheet ◽  
Electrical Steel ◽  
High Speed Steel ◽  
Experimental Methods ◽  
Fem Simulations ◽  
Iron Losses ◽  
Simulation Results ◽  
Electrical Steel Sheet

AbstractOne of the most dominant manufacturing methods in the production of electromechanical devices from sheet metal is punching. In punching, the material undergoes plastic deformation and finally fracture. Punching of an electrical steel sheet causes plastic deformation on the edges of the part, which affects the magnetic properties of the material, i.e., increases iron losses in the material, which in turn has a negative effect on the performance of the electromagnetic devices in the final product. Therefore, punching-induced iron losses decrease the energy efficiency of the device. FEM simulations of punching have shown significantly increased plastic deformation on the workpiece edges with increasing tool wear. In order to identify the critical tool wear, after which the iron losses have increased beyond acceptable limits, the simulation results must be verified with experimental methods. The acceptable limits are pushed further in the standards by the International Electrotechnical Commission (IEC). The new standard (IEC TS 60034-30-2:2016) has much stricter limits regarding the energy efficiency of electromechanical machines, with an IE5 class efficiency that exceeds the previous IE4 class (IEC 60034-30-1:2014) requirements by 30%. The simulations are done using Scientific Forming Technologies Corporation Deform, a finite element software for material processing simulations. The electrical steel used is M400-50A, and the tool material is Vanadis 23, a powder-based high-speed steel. Vanadis 23 is a high alloyed powder metallurgical high-speed steel with a high abrasive wear resistance and a high compressive strength. It is suitable for cold work processing like punching. In the existing literature, FEM simulations and experimental methods have been incorporated for investigating the edge deformation properties of sheared surfaces, but there is a research gap in verifying the simulation results with the experimental methods. In this paper, FEM simulation of the punching process is verified using an electrical steel sheet from real production environment and measuring the deformation of the edges using microhardness measurements. The simulations show high plastic deformation 50 μm into the workpiece edge, a result that is shown to be in good agreement with the experimental results.

scholarly journals Development of Depth-Limited Wave Boundary Layers over a Smooth Bottom

2020 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Xiping Yu ◽  
Guangwei Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Boundary Layers ◽  
Wave Motion ◽  
Numerical Study ◽  
Experiment Data ◽  
Tidal Motion ◽  
Long Period ◽  
Simulation Results ◽  
Wave Boundary

A theoretical and numerical study is carried out to investigate the transformation of the wave boundary layer from non-depth-limited (wave-like boundary layer) to depth-limited one (current-like boundary layer) over a smooth bottom. A long period of wave motion is not sufficient to induce depth-limited properties, although it has simply been assumed in various situations under long waves, such as tsunami and tidal currents. Four criteria are obtained theoretically for recognizing the inception of the depth-limited condition under waves. To validate the theoretical criteria, numerical simulation results using a turbulence model as well as laboratory experiment data are employed. In addition, typical field situations induced by tidal motion and tsunami are discussed to show the usefulness of the proposed criteria.

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