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Seasonal influenza epidemics have been responsible for causing increased economic expenditures and many deaths worldwide. Evidence exists to support the claim that the virus can be spread through the air, but the relative significance of airborne transmission has not been well defined. Particle image velocimetry (PIV) and hot‐wire anemometry (HWA) measurements were conducted at 1 m away from the mouth of human subjects to develop a model for cough flow behavior at greater distances from the mouth than were studied previously. Biological aerosol sampling was conducted to assess the risk of exposure to airborne viruses. Throughout the investigation, 77 experiments were conducted from 58 different subjects. From these subjects, 21 presented with influenza‐like illness. Of these, 12 subjects had laboratory‐confirmed respiratory infections. A model was developed for the cough centerline velocity magnitude time history. The experimental results were also used to validate computational fluid dynamics (CFD) models. The peak velocity observed at the cough jet center, averaged across all trials, was 1.2 m/s, and an average jet spread angle of θ = 24° was measured, similar to that of a steady free jet. No differences were observed in the velocity or turbulence characteristics between coughs from sick, convalescent, or healthy participants.

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Nonlinear energy sinks (NESs) have outperformed tuned mass dampers in mitigating undesired responses against changes in structural frequencies. However, the dilemma of gaining frequency robustness at the cost of energy sensitivity as well as the large masses of devices required for civil engineering structures impede the applications of existing NESs. To solve the issue of lacking energy robustness and take advantage of inerters to reduce physical mass, an asymmetric NES‐inerter (Asym NESI) is developed in this study. This passive inerter‐based nonlinear mass damper is configured based on an energy‐robust NES with an inerter added between the auxiliary mass and a fixed point. The paper commences with the formulation of the Asym NESI through mathematical derivations. Then an Asym NESI is designed and evaluated on a three‐story structure in comparison with other counterpart mass dampers. The effectiveness of the Asym NESI can be attributed to its unique dynamics which are revealed analytically using the harmonic balance method through free vibrations and harmonically forced vibrations. The ensuing numerical validations show that due to the integrated linear and nonlinear dynamics of the Asym NESI, the proposed device exhibits strong robustness against changes in both structural frequency and energy level. Moreover, driven by the large inertial effect induced by the auxiliary inerter, the Asym NESI shows flexibility in choosing a practical installation location without sacrificing excellent control capacity. Importantly, the benefits of the Asym NESI are further confirmed by the responses subjected to a suite of ground motions. This study provides analytical insights into the effectiveness and robustness of Asym NESIs and demonstrates substantial performance enhancement by the inerter in structural response mitigation.