For a non-Newtonian fluid, the mixture viscosity varies depending on the mixture density. Mixture Viscosity and Yield Stressįor soil with suspended particles of minus 10 micrometres (e.g., clay and mud), the chemical forces become significant, causing non-Newtonian flow behaviour. Measuring the soil particle size distribution using a hydrometer can be crucial when significant amounts of fine particles are present.Īpparent viscosity has been included in PnP v1.6.9 to refine production estimates’ accuracy, as requested by users, even though its impact on the production estimate is generally small. The fine particles, i.e., of less than 63 micrometres, affect apparent viscosity, a phenomenon discovered by Albert Einstein in 1905. However, since this influence is typically small, approximating the temperature is usually enough for an accurate production estimate. A higher temperature reduces the water’s viscosity, making it easier to flow. The viscosity of water depends on its temperature, which should be entered into PnP in either Celsius or Fahrenheit. PnP helps users by focusing on the most influential mixture properties, as shown in the figure below. Consequently, yield stress should always be taken into account in order to accurately estimate suction and discharge production. Furthermore, the mixture’s yield stress significantly affects the pipeline’s characteristics. For non-Newtonian fluids, yield stress also affects its behaviour. If the soil-water mixture contains a significant amount of very fine particles in suspension, then the flow behaviour can become non-Newtonian.Īlthough viscosity is constant for Newtonian fluids, the viscosity of non-Newtonian fluids varies as a function of the mixture density. As for fine granular soils, the carrier fluid can become more viscous due to suspended fine particles. Water viscosity is only relevant for medium to coarse granular soils. It can also help users identify and enter the right mixture properties. The latest version of Pumps ‘n Pipeline (PnP), i.e., v1.6.9, can simulate any soil-water mixture in order to estimate production. In order to determine suction and discharge production, successfully characterising soil-mixture viscosity can be key.