Ricerche di Matematica最新文献_第8页

Spectral and Energy–Lyapunov stability of streamwise Couette–Poiseuille and spanwise Poiseuille base flows 沿流库埃-泊泽维尔和沿展向泊泽维尔基流的谱和能量-李雅普诺夫稳定性

4区数学

Ricerche di Matematica Pub Date : 2023-09-16 DOI: 10.1007/s11587-023-00815-8

Andrea Giacobbe, Carla Perrone

{"title":"Spectral and Energy–Lyapunov stability of streamwise Couette–Poiseuille and spanwise Poiseuille base flows","authors":"Andrea Giacobbe, Carla Perrone","doi":"10.1007/s11587-023-00815-8","DOIUrl":"https://doi.org/10.1007/s11587-023-00815-8","url":null,"abstract":"Abstract When a fluid fills an infinite layer between two rigid plates in relative motion, and it is simultaneously subject to a gradient of pressure not parallel to the motion, the base flow is a combination of Couette–Poiseuille in the direction along the boundaries’ relative motion, but it also possess a Poiseuille component in the transverse direction. For this reason the linearised equations include all variables x , y , z , and not only explicitly two variables x , z as it typically happens in the literature. For convenience, we indicate as streamwise the direction of the relative motions of the plates, and spanwise the orthogonal direction. We use Chebyshev collocation method to investigate the monotonic behaviour of the energy along perturbations of general streamwise Couette–Poiseuille plus spanwise Poiseuille base flow, thus obtaining energy-critical Reynolds numbers depending on two parameters. We finally compute the spectrum of the linearisation at such base flows, and hence determine spectrum-critical Reynolds numbers depending on the two parameters. The choice of convex combinations of Couette and Poiseuille flows along the streamwise direction, and spanwise Poiseuille flow, affects the value of the energy-critical Reynolds and wave numbers in interesting ways. Also the spectrum-critical Reynolds and wave numbers depend on the type of base flow in peculiar ways. These dependencies are not described in the literature.","PeriodicalId":21373,"journal":{"name":"Ricerche di Matematica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135304632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Excitable FitzHugh-Nagumo model with cross-diffusion: long-range activation instabilities 具有交叉扩散的可激FitzHugh-Nagumo模型:远程激活不稳定性

4区数学

Ricerche di Matematica Pub Date : 2023-09-12 DOI: 10.1007/s11587-023-00814-9

G. Gambino, M. C. Lombardo, R. Rizzo, M. Sammartino

引用次数: 0

Excitable FitzHugh-Nagumo model with cross-diffusion: close and far-from-equilibrium coherent structures 交叉扩散的可激FitzHugh-Nagumo模型:接近和远离平衡的相干结构

4区数学

Ricerche di Matematica Pub Date : 2023-09-11 DOI: 10.1007/s11587-023-00816-7

G. Gambino, M. C. Lombardo, R. Rizzo, M. Sammartino

{"title":"Excitable FitzHugh-Nagumo model with cross-diffusion: close and far-from-equilibrium coherent structures","authors":"G. Gambino, M. C. Lombardo, R. Rizzo, M. Sammartino","doi":"10.1007/s11587-023-00816-7","DOIUrl":"https://doi.org/10.1007/s11587-023-00816-7","url":null,"abstract":"Abstract In this paper, we shall study the formation of stationary patterns for a reaction-diffusion system in which the FitzHugh-Nagumo (FHN) kinetics, in its excitable regime, is coupled to linear cross-diffusion terms. In (Gambino et al. in Excitable Fitzhugh-Nagumo model with cross-diffusion: long-range activation instabilities, 2023), we proved that the model supports the emergence of cross-Turing patterns, i.e., close-to-equilibrium structures occurring as an effect of cross-diffusion. Here, we shall construct the cross-Turing patterns close to equilibrium on 1-D and 2-D rectangular domains. Through this analysis, we shall show that the species are out-of-phase spatially distributed and derive the amplitude equations that govern the pattern dynamics close to criticality. Moreover, we shall classify the bifurcation in the parameter space, distinguishing between super-and sub-critical transitions. In the final part of the paper, we shall numerically investigate the impact of the cross-diffusion terms on large-amplitude pulse-like solutions existing outside the cross-Turing regime, showing their emergence also in the case of lateral activation and short-range inhibition .","PeriodicalId":21373,"journal":{"name":"Ricerche di Matematica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135935276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A note on the Caristi fixed point theorem 关于Caristi不动点定理的注解

4区数学

Ricerche di Matematica Pub Date : 2023-09-11 DOI: 10.1007/s11587-023-00812-x

Oleg Zubelevich

引用次数: 0

Compound transmuted family of distributions: properties and applications 复合变形分布族：性质和应用

IF 1.2 4区数学

Ricerche di Matematica Pub Date : 2023-08-28 DOI: 10.1007/s11587-023-00808-7

Coşkun Kuş, K. Karakaya, Caner Tanış, Y. Akdoğan, Sümeyra Sert, Fahreddin Kalkan

引用次数: 0

Throughflow effect on bi-disperse convection 双分散对流的通流效应