Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 82, Issue 1 (2021) 96-104 96 Journal of Advanced Research in Fluid Mechanics and Thermal Sciences Journal homepage: www.akademiabaru.com/arfmts.html ISSN: 2289-7879 Boundary Layer Flow, Heat and Mass Transfer of Cu-Water Nanofluid over a Moving Plate with Soret and Dufour Effects: Stability Analysis Najwa Najib 1,* , Norfifah Bachok 2 1 Center of American Education, INTI International University, Persiaran Perdana BBN, 71800 Nilai, Negeri Sembilan, Malaysia 2 Department of Mathematics and Institute for Mathematical Research, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia ARTICLE INFO ABSTRACT Article history: Received 28 August 2020 Received in revised form 2 March 2021 Accepted 5 March 2021 Available online 14 April 2021 Our main focus in this paper is to investigate the effects of Soret and Dufour known as thermodiffusion and diffusion-thermo on moving plate in copper water nanofluid. The set of partial differential equations are converted into set of ordinary differential equations using the appropriate similarity variables before being solved numerically using bvp4c code in Matlab software. The results of heat and mass transfer, temperature and concentration profiles on Soret as well as Dufour effects are presented graphically. Soret effect increases the heat transfer rate at the surface while Dufour effect decreases the mass transfer rate at the surface. Since the solutions exist in dual, we carry out the stability solutions to determine which solution is stable and hence the physical meaning is realized physically. Keywords: Soret and Dufour effects; stability analysis; moving plate; nanofluid 1. Introduction The consideration of Soret effect (thermodiffusion) and Dufour effect (diffusion-thermo) in some literature has gain an attraction due to their significance of study when density difference existed in the flow regime [1]. Soret effect can be described as diffusion of particles from higher temperature towards lower temperature (temperature gradient) due to mass flux. Dufour effect is a reverse phenomenon of Soret effect where particles are diffused from higher concentration to the lower concentration due to energy flux. Both effects have been set up in crystal growth process where the behaviour of convective flows has a strong effect on the temperature and solute temporal variations which lead to nonuniform crystal growth and undesirable nonhomogeneous crystals [2]. Apart from that, many applications of thermodiffusion in industrial processes such in fabrication of semiconductor devices in molten metal and semiconductor mixtures, separation of polymers and DNA as well as in optimum oil recovery from hydrocarbon reservoirs [3]. Kafoussias and Williams [4] are among the first researchers who discovered the existence and development of Soret and Dufour effects on mixed convection with temperature dependent viscosity. Some literatures on moving plate under consideration of Soret and Dufour effects have been listed in [5-10]. * Corresponding author. E-mail address: najwa.mohdnajib@newinti.edu.my https://doi.org/10.37934/arfmts.82.1.96104