Efficient thermal management is critical for future electric aircraft. An innovative approach (Outer Mold Line cooling) leverages the aircraft’s aerodynamic surfaces for heat dissipation, heating the adjacent boundary layer. It is known that wall-heating can have detrimental effects on laminar–turbulent transition driven by stationary crossflow instabilities (S-CFI). However, its impact remains largely unclear due to a lack of experimental studies. This work investigates the effect of a heated wall across all stages of S-CFI development, spanning linear growth, non-linear saturation, and laminar-turbulent transition. This is achieved through comprehensive wind-tunnel experiments, complemented by comparisons with Compressible Nonlinear Parabolized Stability Equations (CNPSE) results. Results show that wall-heating increases the boundary-layer momentum deficit and the crossflow velocity component, leading to increased destabilization of S-CFI. In turn, higher S-CFI amplitudes promote an earlier onset of non-linear interactions between stationary, traveling, and secondary instability modes. Notably, under equivalent freestream turbulence (Tu[jls-end-space/]) levels, wall-heating results in a higher S-CFI saturation amplitude compared to adiabatic conditions. In addition, spectral analysis reveals substantial amplification of unsteady perturbations with wall-heating. A key finding of this work is the strong destabilization of traveling CFI under wall-heating, which persists into the nonlinear regime and yields highly amplified type-III instabilities. One possible implication of the strong destabilization of T-CFI and type-III instabilities is that at sufficiently high wall-to-freestream temperature ratios, T-CFI could dominate the transition process, potentially leading to a transition scenario similar to that observed under high levels of freestream turbulence. ... Read more

Laminar drag reduction is a critical technology for enhancing the endurance and station-keeping capabilities of airship platforms. However, existing transport-based transition models fail to account for the premature transition induced by wall heating, a limitation that significantly hinders the robust engineering application of laminar-flow technology in realistic thermal environments. To address this deficiency, this study first develops stability-based correction for transition modeling that explicitly incorporates wall-to-freestream temperature ratios. Leveraging the Falkner–Skan–Cooke (FSC) equations and linear stability theory (LST) with the eN method, we derive physics-based correlations for the transition criteria as functions of the temperature ratio, pressure gradient, and turbulence intensity. These corrections are integrated into a simplified stability-based transition transport model proposed by [1] and validated against the classic Schubauer and Klebanoff flat-plate experiments, demonstrating accurate prediction of transition locations under adiabatic, heated, and cooled conditions. Crucially, wind-tunnel experiments on a heated airship model show that wall-heating sensitivity depends strongly on local pressure-gradient variations due to Reynolds-number-driven shifts in transition location. The proposed model successfully reproduces the experimentally observed upstream transition shift caused by wall heating. This framework, covering both heating and cooling regimes, provides a capability to support future laminar-flow control technologies based on wall-temperature modulation. ... Read more