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Tasawar Hayat,Salman Ahmad,Muhammad I. Khan,Muhammad I. Khan,Ahmed Alsaedi 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.3
The present work aims to report the consequences of DarcyeForchheimer medium in flow of Cross fluidmodel toward a stretched surface. Flow in porous space is categorized by DarcyeForchheimer medium. Further heat transfer characteristics are examined via thermal radiation and heat generation/absorption. Transformation procedure is used. The arising system of nonlinear ordinary differential equations issolved numerically by means of shooting method. The effects of different flow variables on velocity,temperature, concentration, skin friction, and heat transfer rate are discussed. The obtained outcomesshow that velocity was enhanced with the increase in the Weissenberg number but decays withincrease in the porosity parameter and Hartman number. Temperature field is boosted by thermal radiationand heat generation; however, it decays with the increase in the Prandtl number.
Tasawar Hayat,Muhammad Ijaz Khan,Muhammad Waqas,Ahmed Alsaedi 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.8
This investigation explores the thermally stratified stretchable flow of an Oldroyd-B material bounded bya linear stretched surface. Heat transfer characteristics are addressed through thermal stratification andheat generation/absorption. Formulation is arranged for mixed convection. Application of suitabletransformations provides ordinary differential systems through partial differential systems. The homotopyconcept is adopted for the solution of nonlinear differential systems. The influence of several arisingvariables on velocity and temperature is addressed. Besides this, the rate of heat transfer is calculated andpresented in tabular form. It is noticed that velocity and Nusselt number increase when the thermalbuoyancy parameter is enhanced. Moreover, temperature is found to decrease for larger values of Prandtlnumber and heat absorption parameter. Comparative analysis for limiting study is performed andexcellent agreement is found.
ACCURATE SOLUTION FOR SLIDING BURGER FLUID FLOW
Muhammad Zubair,Tasawar Hayat 한국전산응용수학회 2019 Journal of applied mathematics & informatics Vol.37 No.5
This article addresses the influence of partial slip condition in the hydromagnetic flow of Burgers fluid in a rotating frame of reference. The flows are induced by oscillation of a boundary. Two problems for oscillatory flows are considered. Exact solutions to the resulting boundary value problems are constructed. Analysis has been carried out in the presence of magnetic field. Physical interpretation is made through the plots for various embedded parameters.
Sajid Qayyum,Tasawar Hayat,Sabir A. Shehzad,Ahmed Alsaedi 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.8
The main purpose of this article is to describe the magnetohydrodynamic stagnation point flow ofWalter-B nanofluid over a stretching sheet. The phenomena of heat and mass transfer are based on theinvolvement of thermal radiation and chemical reaction. Characteristics of Newtonian heating are givenspecial attention. The Brownian motion and thermophoresis models are introduced in the temperatureand concentration expressions. Appropriate variables are implemented for the transformation of partialdifferential frameworks into sets of ordinary differential equations. Plots for velocity, temperature, andnanoparticle concentration are displayed and analyzed for governing parameters. The skin friction coefficientand local Nusselt and Sherwood numbers are studied using numerical values. The temperatureand heat transfer rate are enhanced within the frame of the thermal conjugate parameter.
ACCURATE SOLUTION FOR SLIDING BURGER FLUID FLOW
ZUBAIR, MUHAMMAD,HAYAT, TASAWAR The Korean Society for Computational and Applied M 2019 Journal of applied mathematics & informatics Vol.37 No.5
This article addresses the influence of partial slip condition in the hydromagnetic flow of Burgers fluid in a rotating frame of reference.The flows are induced by oscillation of a boundary. Two problems for oscillatory flows are considered. Exact solutions to the resulting boundary value problems are constructed. Analysis has been carried out in the presence of magnetic field. Physical interpretation is made through the plots for various embedded parameters.
Wu Huang,Feng Ding,Tasawar Hayat,Ahmed Alsaedi 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.4
This paper considers the gradient based identification problem of a multivariate output-error system. By using the auxiliary model identification idea and the coupling identification concept, an auxiliary model basedstochastic gradient (AM-SG) algorithm and a coupled AM-SG algorithm are presented. The results indicate that theparameter estimation errors converge to zero under the persistent excitation conditions. The simulation examplesconfirm the theoretical results.
Decomposition-based Gradient Estimation Algorithms for Multivariable Equation-error Systems
Xian Lu,Feng Ding,Ahmed Alsaedi,Tasawar Hayat 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.8
This paper concerns the parameter identification methods of multivariable equation-error systems. By means of the decomposition technique, the multivariable identification model is transformed into two subidentification models and a decomposition-based stochastic gradient (D-SG) algorithm is presented for estimating the parameters of these two submodels. In order to further improve the convergence rate and the parameter estimation accuracy, we expand the innovation vectors to the innovation matrices and develop a decomposition-based multi-innovation stochastic gradient (D-MISG) algorithm. The simulation results confirm that the D-MISG algorithm can provide more accurate parameter estimates than the D-SG algorithm.
Yihong Zhou,Feng Ding,Ahmed Alsaedi,Tasawar Hayat 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.11
This paper studies some parameter estimation algorithms for a class of nonlinear models with exponential terms, i.e., the radial basis function-based state-dependent autoregressive (RBF-AR) models. An Aitken-based multi-innovation stochastic gradient algorithm is presented for the RBF-AR models based on the Aitken method. Inspired by the decomposition-coordination principle of large systems, an Aitken-based hierarchical multi-innovation stochastic gradient algorithm is proposed by combining the decomposition technique with the Aitken method. The effectiveness of the proposed algorithms are validated through two simulation examples.
Hierarchical Parameter Estimation for the Frequency Response Based on the Dynamical Window Data
Ling Xu,Weili Xiong,Ahmed Alsaedi,Tasawar Hayat 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4
This paper studies the problem of parameter estimation for frequency response signals. For a linear system, the frequency response is a sine signal with the same frequency as the input sine signal. When a multifrequency sine signal is applied to a system, the system response also is a multi-frequency sine signal. The signal modeling for multi-frequency sine signals is very difficult due to the highly nonlinear relations between the characteristic parameters and the model output. In order to obtain the parameter estimates of the multi-frequency sine signal, the signal modeling methods based on statistical identification are proposed by means of the dynamical window discrete measured data. By constructing a criterion function with respect to the model parameters to be estimated, a hierarchical multi-innovation stochastic gradient estimation method is derived through parameter decomposition. Moreover, the forgetting factor and the convergence factor are introduced to improve the performance of the algorithm. The simulation results show the effectiveness of the proposed methods.