We examine the characteristics of helical flow in a concentric annulus with radii ratios of 0.52 and 0.9, whose outer cylinder is stationary and inner cylinder is rotating. Pressure losses and skin friction coefficients are measured for fully developed flows of water and a 0.4% aqueous solution of sodium carboxymethyl cellulose (CMC), when the inner cylinder rotates at the speed of 0~62.82 rad/...

Flat plate skin friction calculations over a range of Mach numbers from 0.4 to 3.5 at Reynolds numbers from 16 million to 492 million using a Navier Stokes method with advanced turbulence modeling are compared with incompressible skin friction coefficient correlations. The semi-empirical correlation theories of van Driest; Cope; Winkler and Cha; and Sommer and Short T’ are used to transform the...

Negative skin friction occurs when concrete piles are situated in soft soils, consolidating soilmass, etc., resulting in a downward force that increases loading on shaft piles and reduces the bearing capacity of the piles. A new concept based on the shifting rate of piles, and the settlement rate of the surrounding soils has been suggested far the study of negative skin friction. Negative skin ...

The adversarial structure of the American judicial system encourages critical reviews and challenges of forensic evidence. As a result, the discriminatory power of friction ridge skin impression evidence has been a prime target of debate among critics of the latent print discipline for years, the primary argument being friction ridge skin examination is neither scientif ically reliable nor lega...

Mechanism Study on Tactile Perception Evoked by Skin Friction Si Chen 2016 The mechanism study on tactile perception evoked by skin friction is mainly the analysis of relationship between skin Physiology and object surface properties. It is the basis of research on human discriminative touch. It is significant to the fields of haptics, development of artificial skin, virtual reality, and medica...

The friction coefficients have been used to evaluate skin care and cosmetic products which aim at conferring smoothness to skin. Cosmetic products are thought to perform their function by depositing sufficient amounts of desirable ingredients leading to perceptible change in adhesion and friction coefficients. We design the friction coefficients measurement system which is assembled with multi-...

The role of contact pressure on skin friction has been documented in multiple experimental studies. Skin friction significantly raises in the low-pressure regime as load increases while, after a critical pressure value is reached, the coefficient of friction of skin against an external surface becomes mostly insensitive to contact pressure. However, up to now, no study has elucidated the qualit...

Skin can be damaged by the environment easily. Skin cream is an effective and rapid way to moisten the skin by changing the skin surface properties. Rat skin and pig skin are common animal models for studies and were used as skin samples in this study. The nano- and macroscale friction and durability of damaged skin were measured and compared with those of virgin (intact/undamaged) skin. The ef...

This work focuses on the friction in contacts where the human finger pad is one of the interacting surfaces. This 'tactile friction' requires a full understanding of the contact mechanics and the behaviour of human skin. The coefficient of friction cannot be considered as a property of the skin alone, but depends on the entire tribo-system. In this work, frictional forces were measured using a ...