![]() ![]() 1 Newton’s Law of Viscosity approximates the behaviour of Newtonian fluids. Force / Area = Shear stress τ = -η (du / dy)įig. Fluids obeying this law experience a shear stress between layers which is proportional to the negative value of the velocity gradient between them. Such materials are considered non-Newtonian fluids: their viscosities, measures of resistance to deformation under stress, change under stress, unlike Newtonian fluids which, at constant temperatures, have constant viscosities under stress and are accurately described by Newton’s Law of Viscosity (Fig. This investigation is centred around the rheology, the study of flow, particularly in materials with both fluid and solid properties. Unexpected and inconclusive results are also yielded determination of their origin involves review of the experimental method and possible causes of unanticipated behaviour. Analysis also strongly indicates an inverse, non-linear relationship between temperature and viscosities for both honeys, with viscosity affected most within the lower temperature interval of 20 ⁰C - 30 ⁰C. Graphical and computational analysis of clear and heather honey finds evidence of a linear inverse relationship between force applied over time and viscosity in clear honey, a property termed ‘thixotropy’. The aim of this project is to investigate the rheological properties and the effect of temperature on the viscosity of honey by comparing two different types (clear honey and heather honey). Since non-Newtonian behaviour is observed and the ideal-world assumptions required are not strictly obeyed, results derived using Newtonian mechanical are considered approximate models. This equation uses simplified Newtonian mechanics to equate upward and downward forces at terminal velocity, relating the time taken for travel through a honey sample to its viscosity. By treating a spherical ball-bearing descending through honey as a particle and the honey as a fluid exhibiting laminar flow, and making a number of other assumptions, data can be acquired for use in Stokes’ equation. Storage temperature and physical disturbance are two factors known to affect the viscosity of certain honeys. One such property is a viscosity (often thought of as ‘thickness’ or resistance to pouring) prone to change depending on the conditions in which it is kept. Some household honeys are known to exhibit interesting ‘non-Newtonian’ properties. Rheology and Temperature-Dependent Viscosity of Honeys Abstract ![]()
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