Perception and Sensitivity to Horizontal Turbulent Air Flows at the Head Region

Abstract

This work deals with experimental investigations on human reaction to local air movements of people in global thermal comfort, performing light activity. An analysis on draught risk was developed comparing the results with previous research findings on human response to draught. The intensity of air velocity, in terms of mean value and relative turbulence, was referred to the level at which normally clothed people could perceive and feel air movements behind the neck, in global neutral thermal condition. This work provides evidence of how the exposure duration to air movements plays a fundamental role on air flow sensitivity. The human reaction to an air flow was observed to vary with exposure duration: the feeling changes in intensity while the air flow persists blowing constantly. Moreover, different reactions have been observed between female and male test persons. Although these results were observed in the typical situation of horizontal air jet flows blowing from behind, they could apply in climatically controlled environments, where air flow is supplied horizontally at low speed, and the occupants are sitting far from the inlet section.

Human perception of room temperature and intermittent air jet cooling in a classroom

“…Thus airflow variations can be employed as a method for cooling, but whereas some studies suggest that this method improves thermal comfort and perceived air quality (PAQ) others show that if not well controlled could introduce problems such as agitation, dry eyes, difficulties in breathing and tension skin. [19][20][21] This study explores two methods of retaining occupants comfort in a classroom: (1) reducing room air temperature and (2) increasing convective and evaporative cooling with controlled intermittent air jet cooling. The latter method optimizes elevated air movements by the use of high momentum ceiling mounted diffusers that generate intermittent confluent jets that merge to form a long-horizontal two dimensional single jet.…”

“…14 The air jets are deliberately projected downwards targeting the head because it is a sensitive region of a fully dressed person and the thermal perception is influenced by external air movements supplied around it. 20 The purpose of the present paper is to investigate and verify the effect of heat on occupants and how cooling by reducing the room temperature would compare with cooling by intermittent air jets (convective cooling) in classrooms. To achieve this, two experiments were conducted in a full scale mockup classroom at the University of Ga¨vle.…”

Aerotactile Integration from Distal Skin Stimuli

“…Airflow on the skin and hair can generate many distinct percepts: Evidence shows airflow stimuli can generate sensations of cold (Todde, 2000), hair displacement sensory reactions (Hamalainen et al , 1985), and responses in the remaining four mechanoreceptor types (Mizobuchi et al , 2000). Hair and hair mechanoreceptors are important for detecting airflow direction properly, especially at low airflow pressures.…”

“…Without the hair displacement sense, it is generally believed airflow is more likely to be detected as pressure or coldness alone, and not airflow (see Todde, 2000). Hairy skin also has sensors devoted to pleasant touch, and the influence of these on airflow sensation is unknown and as a result potentially relevant (Löken, 2009).…”

Objective recognition of cough sound as biomarker for aerial pollutants

“…In contrast to, for example, acoustic rhinometry and nasal lavage biomarkers (Walinder et al., 2001) such a sound‐analysis‐based biomarker has an objective contactless non‐invasive nature and is expandable toward other spatial dimensions and a varying number of individuals. In addition, a sound‐analysis‐based biomonitor for air quality is an interesting on‐line model input for flow control aiming to improve respiratory health (Collignan and Riberon, 2000; Todde, 2000; Xing et al., 2000; Xu and Chen, 2000).…”