Viscous scaling laws for wall shear stress in asymmetric twin-jet impingement

Abstract

Asymmetric twin impinging jets are widely utilized in various engineering fields, but the fundamental physics of nonlinear ground loads under momentum imbalance remains unclear. In this study, steady-state computational fluid dynamics simulations are performed to construct an extensive database consisting of 399 cases. A support vector machine classifier is employed to establish a continuous probabilistic topology map for fountain and washout regimes, where representative flow fields confirm that sustained centered fountain formation remains confined to a narrow parameter pocket near macroscopic momentum balance and moderate nozzle spacing. Despite the geometric and kinematic complexities of asymmetric interactions, the maximum wall shear stress follows the classical viscous scaling behavior, W S S max ∝ V max 1.81 . The systematic deviations from this baseline are incorporated into a physics-constrained interaction-corrected scaling formulation through a continuous correction kernel for plume-interaction effects. The formulation reproduces the calibration database with an in-sample R 2 = 0.9391 , and on a regime-rebalanced subset of the same data it reaches R 2 = 0.9095 , whereas the baseline falls to R 2 = 0.8086 . Under 5-fold cross-validation, the formulation remains at least as accurate as the baseline, with a smaller fold-to-fold variance. On an independent 34-case test set, the model reduces the mean absolute error from 0.4079 to 0.3868 overall, and the improvement concentrates in the near-balanced far-field subset, where it decreases from 0.6032 to 0.1913. This study connects global flow topology, classical viscous scaling, and a regime-informed estimation of peak ground loading.