Numerical Investigation of the Mechanisms of Instabilities and Transition to Turbulence in Laminar Separation Bubbles by Means of Isotropic Perturbations

• Grant number: 25/18807-5
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 01, 2026
• End date: March 31, 2027
• Field of knowledge: Engineering - Aerospace Engineering - Aerodynamics
• Principal Investigator: Elmer Mateus Gennaro
• Grantee: Renan Trevizan de Melo
• Supervisor: Daniel Rodriguez Alvarez
• Host Institution: Faculdade de Engenharia. Universidade Estadual Paulista (UNESP). Campus São João da Boa Vista. São João da Boa Vista , SP, Brazil
• Institution abroad: Universidad Politécnica de Madrid (UPM), Spain
• Associated to the scholarship: 24/00149-9 - Numerical Investigation of Instability Mechanisms and Transition to Turbulence in Laminar Separation Bubbles through Isotropic Disturbances., BP.DR

Abstract

This project focuses on the numerical investigation of free-stream turbulence (FST) and hydrodynamic instability mechanisms to understand the transition to turbulence in laminar separation bubbles (LSBs). The physical behavior of separated flows is highly complex due to the intrinsic coupling between flow separation and transition. This complexity is further amplified in the presence of external perturbations, such as FST, which introduce competing instability pathways. To address this challenge, the project proposes the controlled introduction of isotropic disturbances with varying intensities into the freestream, enabling the analysis of transition scenarios representative of real-world aerodynamic conditions. The research will be carried out through direct numerical simulations (DNS), allowing a high-fidelity analysis of the interaction between FST and LSBs. This stage of the project will be developed at the Universidad Politécnica de Madrid, under the supervision of Prof. Dr. Rodríguez Álvarez Daniel. The core goal is to integrate a synthetic turbulence generator into an existing DNS framework, providing precise inflow conditions for transitional simulations. By exploring the dominant instability mechanisms and the influence of FST on separation bubble dynamics, the project aims to generate new insights into transition physics, with practical implications for aerodynamic design and flow control strategies. The expected outcomes include scientific contributions to the understanding of transitional separated flows and improved modeling capabilities for applications in aerospace and related engineering fields.