The linear stability of Walters B viscoelastic fluid-saturated horizontal porous layer is examined theoretically when the walls of the porous layer are subjected to time-periodic temperature modulation. Three types of boundary temperature modulations are considered namely, symmetric, asymmetric, and only the lower wall temperature is modulated while the upper wall is held at constant temperature. A regular perturbation method based on small amplitude of applied temperature field is used to compute the critical values of Rayleigh number and the corresponding wave number. The shift in critical Rayleigh number is calculated as a function of modulation frequency, viscoelastic parameter, and Prandtl number. The effect of all three types of modulations is found to be destabilizing as compared to the unmodulated system. This result is in contrast to the system with other types of fluids. Besides, the influence of physical parameters on the control of convective instability of the system is discussed.
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Acknowledgment One of the authors (ISS) wishes to thank the Brain Korea 21 (BK21) Program of the School of Mechanical Engineering, Yonsei University, Seoul, Korea, for inviting him as a visiting Professor and also the Bangalore University for sanctioning sabbatical leave. The work of MSM is supported by UGC under DRS program. The author SSK wishes to thank the President and Principal of his college for their encouragement and support.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)