Speaker: 丁兆东 (内蒙古大学)
Time: 2025. Jul 11th 17:00-18:00
Location: R1610,SIMIS
Abstract:
Compared to Newtonian fluids, Maxwell fluids exhibit more complex flow behaviors due to elastic effects, particularly in instability and transition processes, where elasticity plays a significant role in disturbance dynamics. This study investigates the linear instability of Maxwell fluid in channel flow using asymptotic analysis and numerical methods. First, the linearized velocity-vorticity equations are derived. Under the zeroth-order long-wave approximation, it is proven that the channel flow of a Maxwell fluid is linearly stable for all Reynolds and Weissenberg numbers. However, when first-order terms are included, instability arises at moderate Weissenberg numbers (Wi > 1). A quantitative analysis of the first-order eigenvalue expression further provides a criterion for first-order perturbation-induced instability. Additionally, by numerically solving the linearized velocity-vorticity equations, the stability spectrum for arbitrary wavelengths is obtained. Comparisons with the spectrum under first-order perturbation reveal qualitative agreement: the flow remains stable at low Weissenberg numbers but becomes unstable as the Weissenberg number increases. These results contribute to understanding and explaining the mechanisms of flow instability induced by elasticity.
About Speaker:
丁兆东，内蒙古大学数学科学学院副教授，应用数学和流体力学专业博士生导师。2013 年 8 月至今在内蒙古大学数学科学学院工作。目前以第一作者在 J. Fluid Mech.，Phys. Fluids，Science China Mathematics，Appl. Math. Mech.- Engl. 等期刊发表多篇论文。主持国家自然科学基金面上、青年项目，以及内蒙古自治区自然科学基金杰青项目、自治区青年科技英才等项目。担任内蒙古自治区数学学会理事，中国仿真学会仿真算法委员会委员，中国仿真学会青年工作委员会委员。
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