Comparison Between the Koopman Modes for the Flow Around Circular Cylinder and Circular Cylinder Fitted with Helical Strakes

Autor(es)

Freire, Cesar M. ; Meneghini, Julio R. ; Gioria, Rafael S. ; Assi, Gustavo R. S. ; Theofilis, V ; Soria, J

• Tipo de documento: Artigo Científico
• Fonte: INSTABILITY AND CONTROL OF MASSIVELY SEPARATED FLOWS; v. 107, p. 6-pg., 2015-01-01.

Resumo

The helical strake is a device commonly employed for vortex-induced vibration attenuation or suppression. It works by changing and affecting the flow patterns around a circular cylinder and, thereby, reducing the interaction of the shear layers formed in this massive separated type of flow. In this paper the wake of vortices generated by a bare circular cylinder is compared to the wake generated by a circular cylinder fitted with helical strake with pitch equal to ten cylinder diameters and height equal to 0.2 of the cylinder diameter. Besides the analysis of the measured velocity field, a Koopman decomposition is made and the most energetic modes obtained for each condition are compared. The Reynolds number for the visualizations is Re = 10,000. (AU)

• Processo FAPESP: 10/00053-9 - Vibração induzida por vórtices com dois graus de liberdade e efeito de interferência
• Beneficiário: Cesar Monzu Freire
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 13/05792-2 - Estudo do controle de escoamentos massivamente separados estudo de caso: supressores de vibração induzida por vórtices do tipo strakes helicoidal
• Beneficiário: Cesar Monzu Freire
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto