Accurate Computation of Flow below the Rotor Disk by a Finite-State Method

2013 ◽  
Author(s):  
Zhongyang Fei ◽  
David Peters
Keyword(s):  
Accurate Computation ◽  
Finite State ◽  
Rotor Disk ◽  
State Method

Finite state induced flow models. II - Three-dimensional rotor disk

1995 ◽  
Vol 32 (2) ◽  
pp. 323-333 ◽  
Author(s):  
David A. Peters ◽  
Cheng Jian He
Keyword(s):  
Three Dimensional ◽  
Flow Models ◽  
Finite State ◽  
Rotor Disk ◽  
Induced Flow

scholarly journals A Finite State Method in the Performance Evaluation of the Bernoulli Serial Production Lines

2020 ◽  
Vol 10 (18) ◽  
pp. 6602
Author(s):  
Neven Hadžić ◽  
Viktor Ložar ◽  
Filip Abdulaj
Keyword(s):  
Large Scale ◽  
Performance Measure ◽  
Production Lines ◽  
Stationary Probability Distribution ◽  
Transition Systems ◽  
Serial Production ◽  
Work In Process ◽  
Finite State ◽  
State Method ◽  
Serial Production Lines

Research on the performance measure evaluation of Bernoulli serial production lines is presented in this paper. Important aspects of the modeling and analysis using transition systems within the Markovian framework are addressed, including analytical and approximation methods. The “dimensionality curse” problems of the large scale and dense transition systems in the production system engineering field are pointed out as one of the main research and development obstacles. In that respect, a new analytically-based finite state method is presented based on the proportionality property of the stationary probability distribution across the systems’ state space. Simple and differentiable expressions for the performance measures including the production rate, the work-in-process, and the probabilities of machine blockage and starvation are formulated. A finite state method’s accuracy and applicability are successfully validated by comparing the obtained results against the rigorous analytical solution.

scholarly journals Accuracy of Semi-Analytical and Numerical Approaches in the Evaluation of Serial Bernoulli Production Lines

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1461
Author(s):  
Viktor Ložar ◽  
Neven Hadžić ◽  
Tihomir Opetuk ◽  
Vedran Slapničar
Keyword(s):  
Performance Measures ◽  
Analytical Approach ◽  
Manufacturing Industry ◽  
Production Systems ◽  
Numerical Approach ◽  
Production Lines ◽  
State Behavior ◽  
Finite State ◽  
State Method ◽  
Numerical Approaches

The manufacturing industry has a great impact on the economic growth of countries. It is, therefore, crucial to master the skills of the production system by mathematical tools that enable the evaluation of the production systems’ performance measures. Four mathematical approaches toward the modeling of steady-state behavior of serial Bernoulli production lines were considered in this study, namely, the analytical approach, the finite state method, the aggregation procedure, and numerical modeling. The accuracy of the performance measures determined using the semi-analytical methods and the numerical approach was validated using numerous theoretical examples and the results obtained using the analytical model. All of the considered methods demonstrated relevant reliability, regardless of the different theoretical backgrounds.

scholarly journals A Numerical Study of a Rotor Induced Flow Based on a Finite-State Dynamic Wake Model.

2021 ◽  
Vol 22 (2) ◽  
pp. 307-324
Author(s):  
L. G. A. Ferreira ◽  
C. C. Pagani Júnior ◽  
E. M. Gennaro ◽  
C. De Marqui Junior
Keyword(s):  
Numerical Study ◽  
Mathematical Formulation ◽  
Problem Formulation ◽  
Flow Induced Vibration ◽  
Finite State ◽  
Practical Engineering ◽  
Rotor Disk ◽  
Induced Flow ◽  
Wake Model ◽  
Rotary Wings

A Helicopter rotor undergoes unsteady aerodynamic loads ruled by the aeroelastic coupling between the elastic blades and the dynamic wake induced by rotary wings. Modeling the dynamic interaction between the structural and aerodynamic fields is a key point to understand aeroelastic phenomena associated with rotor stability, flow induced vibration and noise generation, among others. In this study, we address the Generalized Dynamic Wake Model, which describes the inflow velocity field at the rotor disk as a superposition  of a finite number of induced flow states. It is a mature model that has been validated based on experimental data and numerically investigated from an eigenvalue problem formulation, whose eigenvalues and eigenvectors provide a deeper insight on the dynamic wake behavior. The paper extends the results presented in the literature to date in order to support physical interpretation of inflow states drawn from the finite-state wake model for flight conditions varying from hover to edgewise flight. The discussion of the wake model mathematical formulation is also oriented towards practical engineering applications to fill a gap in the literature.

scholarly journals A Novel Algorithm Combining Finite State Method and Genetic Algorithm for Solving Crude Oil Scheduling Problem

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Qian-Qian Duan ◽  
Gen-Ke Yang ◽  
Chang-Chun Pan
Keyword(s):  
Genetic Algorithm ◽  
Crude Oil ◽  
Real Life ◽  
Solution Space ◽  
Partial Solution ◽  
Entire Solution ◽  
Scheduling Problem ◽  
Finite State ◽  
State Method ◽  
Searching Ability

A hybrid optimization algorithm combining finite state method (FSM) and genetic algorithm (GA) is proposed to solve the crude oil scheduling problem. The FSM and GA are combined to take the advantage of each method and compensate deficiencies of individual methods. In the proposed algorithm, the finite state method makes up for the weakness of GA which is poor at local searching ability. The heuristic returned by the FSM can guide the GA algorithm towards good solutions. The idea behind this is that we can generate promising substructure or partial solution by using FSM. Furthermore, the FSM can guarantee that the entire solution space is uniformly covered. Therefore, the combination of the two algorithms has better global performance than the existing GA or FSM which is operated individually. Finally, a real-life crude oil scheduling problem from the literature is used for conducting simulation. The experimental results validate that the proposed method outperforms the state-of-art GA method.

scholarly journals Statistical Evaluation of Semi-Analytical, Analytical, and Numerical Models of the Serial Production Lines

2021 ◽  
Vol 15 (3) ◽  
pp. 417-421
Author(s):  
Viktor Ložar ◽  
Tihomir Opetuk ◽  
Hrvoje Cajner ◽  
Neven Hadžić ◽  
Jerolim Andrić
Keyword(s):  
Analytical Approach ◽  
Manufacturing Industry ◽  
Numerical Models ◽  
Numerical Approach ◽  
Production Lines ◽  
Serial Production ◽  
Finite State ◽  
State Method ◽  
Serial Production Lines ◽  
Full Factorial

Production lines are the backbone of the manufacturing industry. To gain the best profit out of a line it is necessary to design each line using the production system engineering. Therefore, three approaches can be used, the numerical, the analytical, and the semi-analytical approach. The aggregation method, finite state method, and the numerical approach are statistically compared concerning the analytical approach using the STATISTICA software. We analyzed the interaction between the input data and the output data for the finite state method in an illustrative example, using a full factorial design and the Design Expert software

Sign in / Sign up

Export Citation Format

Share Document