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In this paper we present the experimental results of a detailed investigation of the flow and acoustic properties of a turbulent jet with Mach number 0·75 and Reynolds number 3·5 10 3 . We describe the methods and experimental procedures followed during the measurements, and subsequently present the flow field and acoustic field. The experiment presented here is designed to provide accurate and reliable data for validation of Direct Numerical Simulations of the same flow. Mean Mach number surveys provide detailed information on the centreline mean Mach number distribution, radial development of the mean Mach number and the evolution of the jet mixing layer thickness both downstream and in the early stages of jet development. Exit conditions are documented by measuring the mean Mach number profile immediately above the nozzle exit. The fluctuating flow field is characterised by means of a hot-wire, which produced radial profiles of axial turbulence at several stations along the jet axis and the development of flow fluctuations through the jet mixing layer. The axial growth rate of the jet instabilities are determined as function of Strouhal number, and the axial development of several spectral components is documented. The directivity of the overall sound pressure level and several spectral components were investigated. The spectral content of the acoustic far field is shown to be compatible with findings of hot-wire experiments in the mixing layer of the jet. In addition, the measured acoustic spectra agree with Tam's large-scale similarity and fine-scale similarity spectra (Tam et al., AIAA Pap 96, 1996).

Due to natural depletion many mature fields are currently suffering from productivity issues due to halite precipitation in the North Sea. Main actions to prevent or solve this type of scaling issues include increasing flowing pressures (topside choking or velocity strings), but often considered easiest and most economical are fresh water washes to dissolve downhole halite deposits. The main objective of this study is to increase production by optimizing washing sequences. Having an accurate washing schedules predicted allows to anticipate on production degradation and its mitigating actions. To predict production decline due to halite, a virtual flow meter is developed combining a well model (Vertical Lift Performance, known as VLP curve), reservoir model (Inflow Performance Relation, known as IPR curve) and a dynamic model for the extra pressure drops due to deposition. The flow is calculated including the additional pressure drop. The virtual flow meter is calibrated using the last 3-6 months of production data. The Well Desalting Planning Tool (WDPT) makes real-time estimates of short-term pressure drops for each well and finally determines a date to water wash. It shows the schedule in the Planning Dashboard of the web-based WDPT tool. The software can be used to assist the operations department in prioritizing platform visits and optimize production. WDPT is developed as part of company Digital Oil Field (DOF).