Turbulent drag reduction of viscoelastic wormlike micellar gels

Long-chained, viscoelastic surfactant solutions (VES) have been widely employed in the oil and gas industry, particularly hydraulic fracturing gravel-packing operations, where turbulence is commonly reached due to high pumping rates. With this motivation, we experimentally investigate turbulent duct flow of an under-studied class wormlike micellar that forms a gel at room temperature. The fluid characterized via rotational rheometry, velocity Reynolds stress profiles are measured Laser Doppler Anemometry (LDA). Three concentrations investigated increasing numbers. fields water, semi-dilute partially hydrolysed polyacrylamide (HPAM) xanthan gum (XG) used as comparisons. Our study reveals gel-like structure mostly broken down during flow, especially near-wall region results indicate presence water layer. Turbulent low show Newtonian-like field throughout most duct, energy spectra shows ?5/3 power law scale with wavenumber, whereas higher lead drag reduction lower spectral densities large wavenumbers. A comparison polymeric fluids maximum (MDR) comparable drag-reduction effects, decrease shear stresses, increased anisotropy buffer layer streamwise fluctuations near-zero wall-normal fluctuations. At centreline polymers VES significantly reduced all wavenumbers probed. Additionally, MDR regime was bounded by Virk’s asymptote for both gel, which implies similar mechanism MDR.