scholarly journals Experimental and numerical investigations on dynamic response performance of a cable laying vessel in complex operating conditions

2019 ◽  
Vol 11 (5) ◽  
pp. 168781401984785
Author(s):  
Weilong Peng ◽  
Lingling Gao ◽  
Yang Wang ◽  
Shiqiang Li ◽  
Xutao He ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Operating Conditions ◽  
Numerical Investigations ◽  
Cable Laying ◽  
Response Performance

Evaluation of the Dynamic-Response-Based Intact Stability Criterion for Floating Wind Turbines

2015 ◽  
Author(s):  
Marco Masciola ◽  
Xiaohong Chen ◽  
Qing Yu
Keyword(s):  
Wind Speed ◽  
Dynamic Response ◽  
Wind Turbines ◽  
Stability Criterion ◽  
Area Ratio ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Stability Criteria ◽  
Intact Stability ◽  
Overturning Moment

As an alternative to the conventional intact stability criterion for floating offshore structures, known as the area-ratio-based criterion, the dynamic-response-based intact stability criteria was initially developed in the 1980s for column-stabilized drilling units and later extended to the design of floating production installations (FPIs). Both the area-ratio-based and dynamic-response-based intact stability criteria have recently been adopted for floating offshore wind turbines (FOWTs). In the traditional area-ratio-based criterion, the stability calculation is quasi-static in nature, with the contribution from external forces other than steady wind loads and FOWT dynamic responses captured through a safety factor. Furthermore, the peak wind overturning moment of FOWTs may not coincide with the extreme storm wind speed normally prescribed in the area-ratio-based criterion, but rather at the much smaller rated wind speed in the power production mode. With these two factors considered, the dynamic-response-based intact stability criterion is desirable for FOWTs to account for their unique dynamic responses and the impact of various operating conditions. This paper demonstrates the implementation of a FOWT intact stability assessment using the dynamic-response-based criterion. Performance-based criteria require observed behavior or quantifiable metrics as input for the method to be applied. This is demonstrated by defining the governing load cases for two conceptual FOWT semisubmersible designs at two sites. This work introduces benchmarks comparing the area-ratio-based and dynamic-response-based criteria, gaps with current methodologies, and frontier areas related to the wind overturning moment definition.

scholarly journals Dynamic Characterization of Biosensing MEMS Cantilevers with Different Position of the Driving Electrode—Vacuum Response Versus Ambient Conditions

2021 ◽  
Vol 4 (1) ◽  
pp. 30
Author(s):  
Marius Pustan ◽  
Corina Birleanu ◽  
Florina Serdean
Keyword(s):  
Dynamic Response ◽  
Resonant Frequency ◽  
Operating Conditions ◽  
Laser Vibrometer ◽  
Electrode Position ◽  
Ambient Conditions ◽  
Biological Detection ◽  
Lower Electrode ◽  
Mems Resonators ◽  
Mems Cantilevers

The influence of the driving electrode positions on the dynamic response of polysilicon MEMS resonators used in biosensing applications is studied as a function of the operating conditions (vacuum versus free-air operating mode). The scope of this research work is orientated towards identifying the effect of driving electrode position on the dynamic response of sensing MEMS used in biomass detection. The mass-deposition detection is based on the change in the resonant frequency of vibrating elements considering a biological detection film deposited on the oscillating structure. The operating conditions, such as medium pressure, change the behavior of the dynamic response including the resonant frequency, the amplitude, and the velocity of oscillations as well as the quality factor and the loss of energy. The change in the dynamic response of the investigated MEMS cantilevers as a function of the lower electrode position and operating conditions is evaluated using a Polytec Laser Vibrometer. The decrease in the amplitude and velocity of the oscillations if the lower electrode is moved from the beam free-end toward the beam anchor is experimentally monitored. The changes in the response of samples in vacuum are slightly influenced by the electrode position compared with the response of the same sample in ambient conditions. Moreover, the effect of oscillating modes (first, second and third modes) is taken into consideration to improve the dynamical detection of the investigated samples. The obtained results indicate that different responses of MEMS resonators can be achieved if the position of the driving electrode is moved from the cantilever free-end toward the anchor. Indeed, the resonator stiffness, velocity and amplitude of oscillations are significantly modified for samples oscillating in ambient conditions for biological detection compared with their response in vacuum.

The Role of Simulation in the Development of a Fast-Actuation Solenoid C.R. Injection System

2004 ◽  
Author(s):  
Gian Marco Bianchi ◽  
Piero Pelloni ◽  
Giovanni Osbat ◽  
Marco Parotto ◽  
Rita Di Gioia ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Control Strategies ◽  
Fluid Dynamic ◽  
Numerical Approach ◽  
Linear Analysis ◽  
Operating Conditions ◽  
System Model ◽  
Injection System ◽  
Multiple Injection ◽  
Pressure Regulator

Upcoming Euro 4 and Euro 5 emission standards are increasing efforts on injection system developments in order to improve mixture quality and combustion efficiency. The target features of advanced injection system are related to their capability of operating multiple injection with a precise control of amount of fuel injected, low cycle-by-cycle variability and life drift, within flexible strategies. In order to accomplish this task, performance must be optimised since injection system concept development by acting on. The extensive use of numerical approach has been identified as a necessary integration to experiments in order to put on the market high quality injection system accomplishing strict engine control strategies. The modelling approach allows focusing the experimental campaign only on critical issues saving time and costs, furthermore it is possible to deeply understand inner phenomena that cannot be measured. The lump/ID model of the whole system built into the AMESim® code was presented in previous works: particular attention was devoted in the simulation of the electromagnetic circuits, actual fluid-dynamic forces acting on needle surfaces and discharge coefficients, evaluated by means 3D-CFD simulations. In order to assess new injection system dynamic response under multiple injection strategies reproducing actual engine operating conditions it is necessary to find to proper model settings. In this work the integration between the injector and the system model, which comprehends the pump, the pressure regulator, the rail and the connecting-pipes, will be presented. For reproducing the dynamic response of he whole system will be followed a step-by-step approach in order to prevent modelling inaccuracies. Firstly will be presented the linear analysis results performed in order to find injection system own natural frequencies. Secondly based on linear analysis results will be found proper injection system model settings for predicting dynamic response to external excitations, such as pump perturbations, pressure regulator dynamics and injection pulses. Thirdly experimental results in terms of instantaneous flow rate and integrated injected volume for different operating conditions will be presented in order to highlight the capability of the modelling methodology in addressing the new injection system design.

Application of SCES in Improving Dynamic Response of DC Microgrid Bus Voltage

2014 ◽  
Vol 521 ◽  
pp. 431-434
Author(s):  
Yuan Sheng Xiong ◽  
Jian Ming Xu
Keyword(s):  
Dynamic Response ◽  
Feedforward Control ◽  
Dc Microgrid ◽  
Wide Range ◽  
Supercapacitor Energy Storage ◽  
Response Performance ◽  
Dc Bus ◽  
Bus Voltage ◽  
The Stability ◽  
The Impact

To improve the stability of DC bus voltage in DC microgrid, and reduce the impact on microgrid equipments by the DC bus voltage fluctuations, a supercapacitor energy storage (SCES) is designed to connect to the DC bus by the bi-directional converter. The controller is designed by the feedforward control and proportional method with the deadband. The great load disturbance is simulated in PSIM software when the DC microgrid operates in the grid-connected rectification mode. The simulation results show that SCES under the proposed control strategy can reduce the fluctuation range of the DC bus voltage in a wide range of load disturbances, and the dynamic response performance of DC bus voltage is improved.

scholarly journals Numerical investigations of the dynamic response of a floating bridge under environmental loadings

2018 ◽  
Vol 13 (sup1) ◽  
pp. 113-126 ◽  
Author(s):  
Yanyan Sha ◽  
Jørgen Amdahl ◽  
Aleksander Aalberg ◽  
Zhaolong Yu
Keyword(s):  
Dynamic Response ◽  
Numerical Investigations ◽  
Floating Bridge

Steady State and Transient Analysis of Grid Connected Doubly Fed Induction Generator Under Different Operating Conditions

2017 ◽  
Vol 6 (3) ◽  
pp. 174
Author(s):  
Sukhwinder Singh Dhillon ◽  
Jagdeep Singh Lather ◽  
Sanjay Marwaha
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Reference Frames ◽  
Reactive Power ◽  
Operating Conditions ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Rotor Speed ◽  
Doubly Fed ◽  
Matlab Programming

This paper present steady state and dynamic (Transient) models of the doubly fed induction generator connected to grid. The steady state model of the DFIAG (Doubly Fed Asynchronous induction Generator) has been constructed by referring all the rotor quantities to stator side. With the help of MATLAB programming simulation results are obtained to depict the steady state response of electromechanical torque, rotor speed, stator and rotor currents, stator and rotor fluxes, active and reactive drawn and delivered by Doubly fed Asynchronous Induction machine (DFAIM) as it is operating in two modes i.e. generator and motor. The mathematical steady state and transient model of the DFIAM is constructed for three basic reference frames such as rotor, stator and synchronously revolving reference frame using first order deferential equations. The effect of unsaturated and saturated resultant flux on the mutual inductance is also taken into account to deeply understand the dynamic response of the machine. The steady state and dynamic response of the DFAIG are compared for different rotor voltage magnitudes. Also, the effect of variations in mechanical input torque, stator voltage variations are simulated to predict the stator and rotor currents, active and reactive power, electromagnetic torque and rotor speed variations.

scholarly journals Computational Intelligence-Based Optimization Methods for Power Quality and Dynamic Response Enhancement of ac Microgrids

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4063 ◽  
Author(s):  
Touqeer Ahmed Jumani ◽  
Mohd Wazir Mustafa ◽  
Nawaf N. Hamadneh ◽  
Samer H. Atawneh ◽  
Madihah Md. Rasid ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Power Quality ◽  
Computational Intelligence ◽  
Research Work ◽  
Optimization Methods ◽  
Optimization Techniques ◽  
Operating Conditions ◽  
Inference System ◽  
Study Objective ◽  
Comprehensive Review

The penetration of distributed generators (DGs) in the existing power system has brought some real challenges regarding the power quality and dynamic response of the power systems. To overcome the above-mentioned issues, the researchers around the world have tried and tested different control methods among which the computational intelligence (CI) based methods have been found as most effective in mitigating the power quality and transient response problems intuitively. The significance of the mentioned optimization approaches in contemporary ac Microgrid (MG) controls can be observed from the increasing number of published articles and book chapters in the recent past. However, literature related to this important subject is scattered with no comprehensive review that provides detailed insight information on this substantial development. As such, this research work provides a detailed overview of four of the most extensively used CI-based optimization techniques, namely, artificial neural network (ANN), fuzzy logic (FL), adaptive neuro-fuzzy inference system (ANFIS) and genetic algorithm (GA) as applied in ac MG controls from 42 research articles along with their basic working mechanism, merits, and limitations. Due to space and scope constraints, this study excludes the applications of swarm intelligence-based optimization methods in the studied field of research. Each of the mentioned CI algorithms is explored for three major MG control applications i.e., reactive power compensation and power quality, MPPT and MG’s voltage, frequency, and power regulation. In addition, this work provides a classification of the mentioned CI-based optimization studies based on various categories such as key study objective, optimization method applied, DGs utilized, studied MG operating mode, and considered operating conditions in order to ease the searchability and selectivity of the articles for the readers. Hence, it is envisaged that this comprehensive review will provide a valuable one-stop source of knowledge to the researchers working in the field of CI-based ac MG control architectures.

scholarly journals Numerical Investigations of Micro-Scale Diffusion Combustion: A Brief Review

2019 ◽  
Vol 9 (16) ◽  
pp. 3356 ◽  
Author(s):  
P. R. Resende ◽  
Mohsen Ayoobi ◽  
Alexandre M. Afonso
Keyword(s):  
Alternative Fuels ◽  
Numerical Models ◽  
Scientific Progress ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Critical Parameters ◽  
Diffusion Combustion ◽  
Great Opportunity ◽  
Numerical Investigations ◽  
Numerical Approaches

With the increasing global concerns about the impacts of byproducts from the combustion of fossil fuels, researchers have made significant progress in seeking alternative fuels that have cleaner combustion characteristics. Such fuels are most suitable for addressing the increasing demands on combustion-based micro power generation systems due to their prominently higher energy density as compared to other energy resources such as batteries. This cultivates a great opportunity to develop portable power devices, which can be utilized in unmanned aerial vehicles (UAVs), micro satellite thrusters or micro chemical reactors and sensors. However, combustion at small scales—whether premixed or non-premixed (diffusion)—has its own challenges as the interplay of various physical phenomena needs to be understood comprehensively. This paper reviews the scientific progress that researchers have made over the past couple of decades for the numerical investigations of diffusion flames at micro scales. Specifically, the objective of this review is to provide insights on different numerical approaches in analyzing diffusion combustion at micro scales, where the importance of operating conditions, critical parameters and the conjugate heat transfer/heat re-circulation have been extensively analyzed. Comparing simulation results with experimental data, numerical approaches have been shown to perform differently in different conditions and careful consideration should be given to the selection of the numerical models depending on the specifics of the cases that are being modeled. Varying different parameters such as fuel type and mixture, inlet velocity, wall conductivity, and so forth, researchers have shown that at micro scales, diffusion combustion characteristics and flame dynamics are critically sensitive to the operating conditions, that is, it is possible to alter the flammability limits, control the flame stability/instability or change other flame characteristics such as flame shape and height, flame temperature, and so forth.

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