Suppression of limit cycle oscillations in atmospheric entry vehicles using retropropulsive jets
Journal of Mechanics, cilt.42, ss.432-448, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 42
- Basım Tarihi: 2026
- Doi Numarası: 10.1093/jom/ufag027
- Dergi Adı: Journal of Mechanics
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, ABI/INFORM, Compendex, INSPEC, Directory of Open Access Journals, Academic Search Ultimate (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Sayfa Sayıları: ss.432-448
- Anahtar Kelimeler: aerodynamic stability, limit cycle oscillations, nozzle jet pressure ratio, retropropulsive jets
- Orta Doğu Teknik Üniversitesi Adresli: Evet
Özet
Nonlinear dynamic instabilities in blunt-body atmospheric entry vehicles can lead to self-sustained oscillatory motion during transonic and low-supersonic flight, driven by unsteady shock–wake interactions. This study presents an integrated analytical and computational framework for assessing limit cycle oscillations in atmospheric entry capsules equipped with retropropulsive opposing jets. A reduced-order nonlinear pitch model is developed using the multiple time scales method to characterize the onset and relative severity of oscillatory behavior as a function of aerodynamic damping and nonlinear stiffness. These stability-governing parameters are obtained from steady and time-accurate computational fluid dynamics (CFD) simulations using a forced oscillation methodology. To ensure predictive accuracy, the multiple time scales framework is quantitatively validated against direct numerical integration of the governing nonlinear differential equation, demonstrating exact agreement in transient amplitude growth, phase characteristics, and steady-state saturation limits. The computational analysis examines the influence of jet pressure ratio and nozzle placement on static drag characteristics, unsteady aerodynamic response, and shock–wake topology for an Orion-class entry capsule. Results show that jet configurations and varying pressure ratios producing large upstream shock displacement can achieve a drag reduction of upto 50% but may increase flow compliance and promote oscillatory growth. In contrast, distributed jet configurations located near the capsule shoulder stabilize the bow shock, reduce wake unsteadiness, and introduce effective aerodynamic damping that reduces drag overshoots by 14%. Furthermore, the analytical time-history reconstruction is validated directly against the high-fidelity CFD dataset, successfully capturing the complex waveform distortions and aerodynamic phase lags generated by the jet plumes. The combined analytical-computational approach provides a computationally efficient tool for identifying stable design regimes and understanding the mechanisms governing nonlinear dynamic stability during atmospheric entry.