Ioannis NIKOLOS, Vassilis THEOFILIS, Angelos KLOTHAKIS
DOI Number: N/A
Conference number: HiSST-2025-004
During hypersonic cruise, boundary layers on gliding vehicles are partly laminar and partly turbulent. The extent of turbulent flow on the vehicle determines its performance, such that improving the vehicle handling properties and extending its range is intimately related to knowledge of the origins of turbulence, which is assumed to arise on account of laminar flow instability mechanisms. Physical instability mechanisms, involving exponentially or algebraically growing small-amplitude perturbations in laminar boundary layers, remain under intensive investigation. In a subsequent step, promise of improved overall vehicle performance can be expected from physics-based predictions of laminar-
turbulent transition and control of this phenomenon through mitigation of linear instabilities by passive or active means. This review consolidates the state-of-the-art in transition prediction and control for hypersonic waveriders and hypersonic vehicles in general. We first examine the historical evolution of transition research, then review fundamental instability mechanisms, challenges in prediction, and recent advances in numerical modeling. The implications for prediction and control are discussed, and an outlook is provided for future progress.