Vorticity Profiles Research Articles

Proppant transport in a planar fracture: Particle image velocimetry

Particle Image Velocimetry (PIV) is a well established technique used to measure displacements in fluids. Proppant transport and placement is a crucial phase in the process of well completion to stimulate production in gas and oil reservoirs. Proppant (a granular material) is injected along fluids during hydraulic stimulation to prop fractures open after hydrocarbon production is initiated. This work presents results on the use of PIV for the study of the transport of proppant in a large laboratory scale flat vertical fracture. Velocity and vorticity profiles were analyzed for different flow rates during the transport and settlement of the proppant inside the fracture. High flow rates, compatible with field operations are achieved in this setup. The results indicate that vortexes are present in a large portion of the system and that a non-linear interplay between the settling dune and the main vortex seems to determine the time at which a fast dune growth occurs in the fracture.

Mixed properties of magnetohydrodynamic waves undergoing resonant absorption in the cusp continuum

Context. Observations of magnetohydrodynamic (MHD) waves in the structured solar atmosphere have shown that these waves are damped and can thus contribute to atmospheric heating. In this paper, we focus on the damping mechanism of resonant absorption in the cusp continuum. This process takes places when waves travel through an inhomogeneous plasma. Aims. Our aim is to determine the properties of MHD waves undergoing resonant absorption in the cusp continuum in the transition layer of a cylindrical solar atmospheric structure, such as a photospheric pore or a coronal loop. Depending on which quantities dominate, one can assess what type of classical MHD wave the modes in question resemble most. Methods. In order to study the properties of these waves, we analytically determine the spatial profiles of compression, displacement, and vorticity for waves with frequencies in the cusp continuum, which undergo resonant absorption. We confirm these analytical derivations via numerical calculations of the profiles in the resistive MHD framework. Results. We show that the dominant quantities for the modes in the cusp continuum are the displacement parallel to the background magnetic field and the vorticity component in the azimuthal direction (i.e. perpendicular to the background magnetic field and along the loop boundary).

Wave-induced shallow-water monopolar vortex: large-scale experiments

Abstract

Scaling Turbulent Combustion Fields in Explosions

We considered the topic of explosions from spherical high-explosive (HE) charges. We studied how the turbulent combustion fields scale. On the basis of theories of dimensional analysis by Bridgman and similarity theories of Sedov and Barenblatt, we found that all fields scaled with the explosion length scale r0. This included the blast wave, the mean and root mean squared (RMS) profiles of thermodynamic variables, combustion variables, velocities, vorticity, and turbulent Reynolds stresses. This was a consequence of the formulation of the problem and our numerical method, which both satisfied the similarity conditions of Sedov. We performed numerical simulations of 1 g charges and 1 kg charges; the solutions were identical (within roundoff error) when plotted in scaled variables. We also explored scaling laws related to three-phase pyrotechnic explosions. We show that although the scaling formally broke down, the fireball still essentially scaled with the explosion length scale r0. However, the discrete Lagrange particles (DLP) (phase 2) and the heterogeneous continuum model (HCM) of the DLP wakes (phase 3) did not scale with r0, and mean and RMS profiles could differ by a factor of 10 in some regions. This was because the DLP particles and wakes introduced an additional scale that broke the similarity conditions.

Abstract 15940: Wall Shear Stress and Vorticity in Atrial Fibrillation, Pulmonary Hypertension, and Normal Atrial Anatomy Models

Introduction: Atrial fibrillation (AF) is a common cardiac rhythm disorder that is often comorbid with pulmonary hypertension (PH) and other conditions associated with abnormal atrial pressure and/or volume overload. In the setting of atrial dilation, mechanoelectric feedback has been linked to the development of ectopic beats that trigger paroxysmal AF mainly originating from pulmonary veins (PVs). However, the precise mechanisms remain poorly understood. Here, we aimed to characterize atrial wall shear stress (WSS) and vorticity in the left atrium of AF, healthy, and at-risk for AF (PH) patient models to develop predictors of AF risk. Methods: Magnetic resonance imaging and computed tomography data (10 AF, 10 PH, and 10 healthy volunteers) were obtained retrospectively. The left atria were manually segmented from each data set. Four-dimensional flow MRI was performed on one patient to derive PV flow data. The 30 atrial geometries and PV flow conditions were used to run numerical blood flow simulations, and atrial WSS and blood flow vorticity were analyzed. Results: As seen in Figure 1, wall shear stress was highest near the PV roots and on the posterior atrial wall, the most common sources of AF triggers. Average WSS and vorticity were significantly lower in PH patients than in both the healthy (p=0.003(WSS), p=0.011(vorticity)) and AF (p=0.046(WSS), p=0.069(vorticity)) groups. Both WSS (r=-0.66) and vorticity (r=-0.68) were moderately correlated to atrial volume in the PH group. Atrial volume was significantly larger in PH (p<0.001) and AF (p<0.001) groups than in the healthy group. Conclusions: The larger atrial volumes of PH and AF patients lead to altered flow profiles and less frequently flow jet impingement on the atrial wall models, leading to abnormal vorticity and WSS profiles. These long term flow abnormalities may influence the development and/or localization of electrical abnormalities and AF; although further study is needed to confirm this hypothesis.

Stability analysis of flow of active extensile fibers in confined domains.

In this article, we study shear flow of active extensile filaments confined in a narrow channel. They behave as nematic liquid crystals that we assumed are governed by the Ericksen-Leslie equations of balance of linear and angular momentum. The addition of an activity source term in the Leslie stress captures the role of the biofuel prompting the dynamics. The dimensionless form of the governing system includes the Ericksen, activity, and Reynolds numbers together with the aspect ratio of the channel as the main driving parameters affecting the stability of the system. The active system that guides our analysis is composed of microtubules concentrated in bundles, hundreds of microns long, placed in a narrow channel domain, of aspect ratios in the range between 10-2 and 10-3 dimensionless units, which are able to align due to the combination of adenosine triphosphate-supplied energy and confinement effects. Specifically, this work aims at studying the role of confinement on the behavior of active matter. It is experimentally observed that, at an appropriately low activity and channel width, the active flow is laminar, with the linear velocity profile and the angle of alignment analogous to those in passive shear, developing defects and becoming chaotic, at a large activity and a channel aspect ratio. The present work addresses the laminar regime, where defect formation does not play a role. We perform a normal mode stability analysis of the base shear flow. A comprehensive description of the stability properties is obtained in terms of the driving parameters of the system. Our main finding, in addition to the geometry and magnitude of the flow profiles, and also consistent with the experimental observations, is that the transition to instability of the uniformly aligned shear flow occurs at a threshold value of the activity parameter, with the transition also being affected by the channel aspect ratio. The role of the parameters on the vorticity and angular profiles of the perturbing flow is also analyzed and found to agree with the experimentally observed transition to turbulent regimes. A spectral method based on Chebyshev polynomials is used to solve the generalized eigenvalue problems arising in the stability analysis.

Impact of Thoracic Endografting on the Hemodynamics of the Native Aorta: Pre- and Postoperative Assessments of Wall Shear Stress and Vorticity Using Computational Fluid Dynamics

Purpose To quantify the hemodynamic consequences of thoracic endovascular aortic repair (TEVAR) by comparing the preoperative and postoperative wall shear stress (WSS) and vorticity profiles on computational fluid dynamics (CFD) simulations. Materials and Methods The pre- and postoperative computed tomography (CT) scans from 20 consecutive patients (median age 69 years, range 20–87) treated for different thoracic aortic pathologies (11 aneurysms, 5 false aneurysms, 3 penetrating ulcers, and 1 traumatic aortic rupture) were segmented to construct patient-specific CFD models using a meshless code. The simulations were run over the cardiac cycle, and the WSS and vorticity values measured at the proximal and distal landing zones were compared. Results The CFD runs provided 4-dimensional simulations of blood flow in all patients. WSS and vorticity profiles at the proximal landing zone (located in zones 0–3 in 15 patients) varied in 18 and 20 of the cases, respectively; WSS was increased in 11 cases and the vorticity in 9. Pre- and postoperative WSS median values were 4.19 and 4.90 Pa, respectively. Vorticity median values were 40.38 and 39.17 Hz, respectively. Conclusion TEVAR induces functional alterations in the native thoracic aorta, though the prognostic significance of these changes is still unknown. CFD appears to be a valuable tool to explore aortic hemodynamics, and its application in a larger series would help define a predictive role for these hemodynamic assessments.

Study of cyclogenesis of developing and non-developing tropical systems of NIO using NCUM forecasting system

A study has been carried out to understand the similarities and differences in a pair of developing and a non-developing tropical disturbances using NCMRWF Unified Model (NCUM) and the concepts of marsupial theory of tropical cyclogenesis. We focused on two systems, tropical cyclone (TC) Ockhi that attained Very Severe Cyclonic Storm (VSCS) strength, and another system that attained deep depression state, however, subsequently weakened. As per the first hypothesis of Marsupial Paradigm, genesis of both the systems is found to be associated with a westward moving parent disturbance. The pouch region associated with the parent disturbance is identified as a region of enhanced moisture. The vertical profiles of vorticity and convergence show that the pathway of genesis is bottom-up for both the systems. Further analyses have been carried out to understand why the depression failed to attain tropical cyclone strength. It has been evidenced that the vertical wind shear is too high (> 50 ms− 1) in the premises of the depression core during the post-genesis evolution. At the same time, the center of the depression happened to be in the close proximity of a ridge present over central Indian land mass. Additionally, significant evidence of dry air intrusion into the core of the depression is seen in the Total Precipitable Water (TPW) analysis and HYSPLIT back trajectory analysis. Furthermore, the depression immediately interacts with the colder sea water as it moves northwestward. Though the marsupial paradigm of tropical cyclogenesis is applicable in the North Indian Ocean as well, factors such as SST, wind shear, closeness to the land mass may play a critical role in further development of the system.

Measurement of Eulerian vorticity beneath rotating surface waves

In this study, we report experimental verification of the existence of an Eulerian contribution to vortices beneath rotating gravity surface waves. We are motivated by recent theoretical predictions regarding the generation of vortices by surface waves. The first prediction indicates that surface waves which produce vortex lattices at the liquid-gas interface can also produce vorticity beneath them and in the liquid bulk. The second prediction is the existence of an Eulerian contribution to the vorticity, owing to the liquid viscosity. First, we establish that we can generate a vortex lattice at the liquid-air interface using rotating waves, resulting from the superposition of two orthogonal phase-shifted standing waves. Using glycerol-water solution as the liquid, we then conduct Particle Image Velocimetry of tracer particles to measure the velocity and vorticity profiles of the flow beneath the interface. We found that vortices are indeed generated beneath these rotating surface waves. To verify the existence of the Eulerian vorticity, we first measure the vorticity at different values of the liquid layer z < 0. After this, we set a reference vorticity value at a specific z closest to the interface that does not intersect with the waves, and get its ratio with respect to the vorticities at other z. We introduce the computation of the normalized density curves of the vorticity ratios, and compare the peak values to the vorticity prefactor ratios obtained using the theoretical predictions. Our results are in close agreement with the theoretical analysis which accounts for this additional contribution. Our experiments shed light on the mechanism of vorticity generation beneath rotating surface waves.

Unraveling the Mechanism of a Rising Three-Phase Contact Line along a Vertical Surface Using Many-Body Dissipative Particle Dynamics.

We present coarse-grained molecular (many-body dissipative particle) dynamics simulations to unravel the wetting mechanism of spontaneous rise of a liquid thin film along vertical flat and rough surfaces. We show that the displacement of the rising contact line, in single- and double-wall geometry, exhibits a ballistic motion (∼t) followed by a diffusive dynamics (∼[Formula: see text]) during the rise of the liquid thin film against gravity. Dynamic contact angle decreases as the contact line transitions from ballistic to diffusive regime. Explicit analysis of the velocity and vorticity profile in the bulk and in the proximity of the contact line suggests an unsteady flow field behind the rising three-phase contact line. Furthermore, our simulation results indicate that contact line dynamics and the flow field behind the contact line are independent of the surface roughness.

Effects of magnetization relaxation in ferrofluid film flows under a uniform magnetic field

We analyze the magnetization relaxation effects of a ferrofluid film flow governed by the ferrohydrodynamics encompassing the Fokker–Planck magnetization equation in a Couette–Poiseuille configuration subject to an applied uniform stationary magnetic field perpendicular to the boundaries. A solver based on OpenFOAM is programmed to find solutions numerically for the velocity, spin velocity, and magnetization in ferrofluid films under the combined pressure gradient, boundary flow, and magnetic field forcing. The solver is validated by comparison with the classical Couette–Poiseuille flows and the analytic solutions of the magnetization relaxation problem when the product of flow vorticity and relaxation time is much smaller than unit, ΩτB≪1. We compare the effects of magnetization relaxation obtained from the phenomenological magnetization equation with those from the equation derived microscopically. The results obtained from the former equation are not suitable for the description of ferrofluid film flows. Due to the magnetization relaxation effects, a misalignment between the local magnetization and the local magnetic field is observed. The net effects are that the flow is hampered by magnetic fields and it manifests as diminished slopes of vorticity profiles and reduced volumetric flow rates. The magnetization relaxation effects also slow down the spin velocity of particles or change their direction, which leads to an enhanced effective viscosity. The total tangential stress exerted on the moving boundary is higher than that of the classical Couette–Poiseuille flow owing to the addition of a magnetic stress. The magnetization relaxation effect is more significant in cases of ferrofluids with higher relaxation times.

Modelling the Dynamics of Granular Particle Interactions in a Vortex Reactor using a Coupled DPM-KTGF Model

In this work, a shear-driven two-phase particulate flow of monodispersed and polydispersed granular materials has been studied experimentally and numerically as a function of solids concentration and restitution coefficients for different operating speeds N (70 -130 rpm) in a lab-scale rotor-stator agglomeration reactor. A coupled computational fluid-particle dynamics (CFPD) model was developed consisting of a steady-state flow field of the continuous phase coupled to a transient particle tracking of the discrete phase. This was achieved via a one-way coupling between the continuous and the discrete phase by including the effect of drag, lift, pressure gradient, virtual mass forces, as well as granular collisional forces in describing the particle-particle, particle-wall and the fluid-particle interactions. The spatiotemporal evolution of the flow pattern, discrete phase properties, and influence of the operating conditions on the granular properties were characterized. The validation of the numerical model developed in this study was carried out based on the theoretical analysis of the rotor-stator flow and the PIV flow measurements. The results showed that the particle sizes were uniformly distributed within the reactor after steady-state conditions, while a small region of high particle concentration was observed near the rotor due to low vorticity and turbulent intensity around the region. In terms of the operating conditions, the restitution coefficients and the operating speeds do not have a significant influence on the granular properties apart from the small region around the shaft where there is a correlation between these parameters. The particle sizes, however, show a positive correlation with the granular properties. Also, a wider particle size distribution was observed axially towards the stator, which might be attributed to the pumping effect of the Batchelor flow in this direction. It was also concluded that the discrete phase velocity does not seem to vary significantly with the restitution coefficients. Furthermore, the vertical velocity and vorticity profiles give a reasonably good agreement between the CFPD model predictions and PIV measurements. The minor observed deviations were mainly due to some of the experimental limitations rather than the robustness of the CFPD model or the numerical code.

Numerical Simulation of the 30P30N High-Lift Airfoil Noise with Spectral Difference Method

In this Paper, the noise generated from the 30P30N high-lift airfoil is simulated with a high-order spectral difference solver. In the simulation, the inflow Mach number is 0.17, and the Reynolds number based on the inflow velocity and the chord length of the airfoil is . Three angles of attack, which are 4, 5.5, and 8.5 deg, are computed. The time-averaged mean flow fields are compared with the experimental data, which include the velocity and spanwise vorticity profiles in the shear layer of the slat cove, the pressure coefficients on the surface of the airfoil. The dynamic pressure on the surface of the slat is sampled and compared with the experimental data by other researchers, and a good agreement is obtained. The far-field noise spectra, computed with the permeable Ffowcs Williams–Hawkings integration method, also agree well with the experimental data. The tone noise source is studied by analyzing the correlation between the dynamic pressure on the slat cove surface and the near-field noise. It is found that the tone noise is strongly correlated with the dynamic pressure close to the reattachment point on the slat cove surface.

Forcing of the Martian polar annulus by Hadley cell transport and latent heating

AbstractA hierarchy of idealized models is used to investigate the roles of Hadley cell forcing and latent heat release from carbon dioxide condensation in determining the annular potential vorticity structure of the Martian winter polar vortex. The angular momentum conserving the Hadley cell model of Lindzen and Hou with summer hemisphere heating maximum of appropriate strength and latitude produces a strong westerly jet near 60°N, which is similar in strength to the winter polar night jet on Mars. Although the corresponding potential vorticity profile in the angular momentum conserving and thermal wind regions has no annular structure resembling the Martian one, there is an implied δ‐function at the discontinuity in zonal wind. This δ‐function is smoothed out by explicit diffusion in full axisymmetric model integrations forming a partial annular structure, though a local maximum in potential vorticity at the pole persists and is further enhanced when cooling representing the polar night is included. A distinct polar minimum and clear annular potential vorticity structure are obtained, however, when an additional representation of polar latent heating is also included. Full eddy‐permitting shallow‐water model integrations confirm the basic structure obtained by the axisymmetric model and suggest a nominal value of viscosity appropriate as a representation of the effects of eddy mixing. Instability of the polar annulus leads to vacillation‐type behaviour involving eddy growth and annulus disruption, followed by re‐formation under the influence of radiative relaxation. The degree of transience and mean eddy activity both show an increase with stronger latent heating and the resulting deeper polar potential vorticity minimum, showing that mixing in polar regions may be dependent on details of polar carbon dioxide condensation. Vacillation time‐scales are also shown to vary with radiative time‐scales, but through a modification of instability growth rate rather than as a result of direct radiative restoration.

Meso-scale Instability Triggered by Dust Feedback in Dusty Rings: Origin and Observational Implications

Abstract High spatial resolution observations of protoplanetary disks by ALMA have revealed many substructures that are providing interesting constraints on disk physics as well as dust dynamics, both of which are essential for understanding planet formation. We carry out high-resolution, 2D global hydrodynamic simulations, including the effects of dust feedback, to study the stability of dusty rings. When the ring edges are relatively sharp and the dust surface density becomes comparable to the gas surface density, we find that dust feedback enhances the radial gradients of both the azimuthal velocity profile and the potential vorticity profile at the ring edges. This eventually leads to instabilities on meso-scales (spatial scales of several disk scale heights), causing dusty rings to be populated with many compact regions with highly concentrated dust densities. We also produce synthetic dust emission images using our simulation results and discuss the comparison between simulations and observations.

Determining the structure of a laminar detachable current in an open cavity

The paper reports a three-dimensional numerical solution to the test problem about a viscous incompressible liquid flow in the closed square-shaped cavity with a movable upper face. Disadvantages in a mathematical statement of the problem about a flow of fluid in a closed cavity have been identified. A finite element method was applied in order to investigate numerically the structure of a circulating detachable laminar movement of viscous incompressible fluid in an open cavity considering the external flow. The profiles of vorticity, the thickness of a boundary layer, the constituents of velocity components in different cross-sections of the cavity, in the boundary layer, as well as in the blending layer, have been given.Typically, studying laminar currents in cavities employs a model of the cavity with a movable wall. However, such a statement of the problem imposes a restriction on the flow pattern in the form of a straight line of the flow that connects the upper corners of the cavity, which results in the distorted structure of vorticity formation in the cavity in general. Within the framework of the current study, the problem statement that overcomes the specified disadvantage has been proposed. The movement of fluid in a cavity occurs due to the shear stress of the external flow in a channel above the cavity, which rules out the straightness of the flow line, which connects the cavity's corner points. Reliability of the reported results has been confirmed by comparing certain parameters to known experimental data by other authors. The study's scientific result in the form of the vorticity structure of a viscous incompressible laminar flow in an open cavity with a channel is interesting from a theoretical point of view. As regards the practical point of view, the identified structure of the flow makes it possible to define the conditions to control a flow in the cavity and, therefore, allows determining the conditions for optimizing the aerodynamic forces acting on a cavity. The applied aspect of the obtained scientific result is the possibility to employ it for a flow over industrial facilities: buildings, inter-carriage space in a railroad train, etc.

Influence of Bottom Topography on Vortex Stability

AbstractThe effects of topography on the linear stability of both barotropic vortices and two-layer, baroclinic vortices are examined by considering cylindrical topography and vortices with stepwise relative vorticity profiles in the quasigeostrophic approximation. Four vortex configurations are considered, classified by the number of relative vorticity steps in the horizontal and the number of layers in the vertical: barotropic one-step vortex (Rankine vortex), barotropic two-step vortex, and their two-layer, baroclinic counterparts with the vorticity steps in the upper layer. In the barotropic calculation, the vortex is destabilized by topography having an oppositely signed potential vorticity jump while stabilized by topography of same-signed jump, that is, anticyclones are destabilized by seamounts while stabilized by depressions. Further, topography of appropriate sign and magnitude can excite a mode-1 instability for a two-step vortex, especially relevant for topographic encounters of an otherwise stable vortex. The baroclinic calculation is in general consistent with the barotropic calculation except that the growth rate weakens and, for a two-step vortex, becomes less sensitive to topography (sign and magnitude) as baroclinicity increases. The smaller growth rate for a baroclinic vortex is consistent with previous findings that vortices with sufficient baroclinic structure could cross the topography relatively easily. Nonlinear contour dynamics simulations are conducted to confirm the linear stability analysis and to describe the subsequent evolution.

Approaching Earth’s core conditions in high-resolution geodynamo simulations

SUMMARY The geodynamo features a broad separation between the large scale at which Earth’s magnetic field is sustained against ohmic dissipation and the small scales of the turbulent and electrically conducting underlying fluid flow in the outer core. Here, the properties of this scale separation are analysed using high-resolution numerical simulations that approach closer to Earth’s core conditions than earlier models. The new simulations are obtained by increasing the resolution and gradually relaxing the hyperdiffusive approximation of previously published low-resolution cases. This upsizing process does not perturb the previously obtained large-scale, leading-order quasi-geostrophic (QG) and first-order magneto-Archimedes-Coriolis (MAC) force balances. As a result, upsizing causes only weak transients typically lasting a fraction of a convective overturn time, thereby demonstrating the efficiency of this approach to reach extreme conditions at reduced computational cost. As Earth’s core conditions are approached in the upsized simulations, Ohmic losses dissipate up to 97 per cent of the injected convective power. Kinetic energy spectra feature a gradually broadening self-similar, power-law spectral range extending over more than a decade in length scale. In this range, the spectral energy density profile of vorticity is shown to be approximately flat between the large scale at which the magnetic field draws its energy from convection through the QG-MAC force balance and the small scale at which this energy is dissipated. The resulting velocity and density anomaly planforms in the physical space consist in large-scale columnar sheets and plumes, respectively, co-existing with small-scale vorticity filaments and density anomaly ramifications. In contrast, magnetic field planforms keep their large-scale structure after upsizing. The small-scale vorticity filaments are aligned with the large-scale magnetic field lines, thereby minimizing the dynamical influence of the Lorentz force. The diagnostic outputs of the upsized simulations are more consistent with the asymptotic QG-MAC theory than those of the low-resolution cases that they originate from, but still feature small residual deviations that may call for further theoretical refinements to account for the structuring constraints of the magnetic field on the flow.

Vortex competition in coastal outflows

Experiments and field observations have shown that there are at least two modes of behavior for river plumes. In many cases, the plume turns to the right (in the Northern Hemisphere) on leaving the river mouth and follows the direction of Kelvin-wave propagation. Alternatively, a “bulge” can form in the plume and a fraction of the outflow volume becomes trapped near the mouth. This paper discusses how bulge formation can be affected by the vorticity profile at the river mouth. Due to the image effect, regions of cyclonic vorticity tend to propagate rightwards, whereas regions of anticyclonic vorticity propagate leftward upon exit from the source. If an outflow consists of regions of cyclonic vorticity to the left of regions of anticyclonic vorticity, the two image effects are in competition. We explore this phenomenon using a quasi-geostrophic model with piecewise-constant potential vorticity, which allows the vorticity profile at the source to be set as part of the problem. We present analytic solutions valid in the source region and at the head of the plume and show that all of the outflow travels rightwards if and only if the region of cyclonic vorticity is dominant. The initial-value problem for the model is integrated numerically using the method of contour dynamics, and the full parameter space is explored. We find that if the cyclonic and anticyclonic contributions cancel, as in the experiments of Avicola and Huq (2003), then steady solutions are unstable and a bulge can form downstream of the river mouth.

A comparative study of the velocity and vorticity structure in pipes and boundary layers at friction Reynolds numbers up to

This study presents findings from a first-of-its-kind measurement campaign that includes simultaneous measurements of the full velocity and vorticity vectors in both pipe and boundary layer flows under matched spatial resolution and Reynolds number conditions. Comparison of canonical turbulent flows offers insight into the role(s) played by features that are unique to one or the other. Pipe and zero pressure gradient boundary layer flows are often compared with the goal of elucidating the roles of geometry and a free boundary condition on turbulent wall flows. Prior experimental efforts towards this end have focused primarily on the streamwise component of velocity, while direct numerical simulations are at relatively low Reynolds numbers. In contrast, this study presents experimental measurements of all three components of both velocity and vorticity for friction Reynolds numbers$Re_{\unicode[STIX]{x1D70F}}$ranging from 5000 to 10 000. Differences in the two transverse Reynolds normal stresses are shown to exist throughout the log layer and wake layer at Reynolds numbers that exceed those of existing numerical data sets. The turbulence enstrophy profiles are also shown to exhibit differences spanning from the outer edge of the log layer to the outer flow boundary. Skewness and kurtosis profiles of the velocity and vorticity components imply the existence of a ‘quiescent core’ in pipe flow, as described by Kwonet al. (J. Fluid Mech., vol. 751, 2014, pp. 228–254) for channel flow at lower$Re_{\unicode[STIX]{x1D70F}}$, and characterize the extent of its influence in the pipe. Observed differences between statistical profiles of velocity and vorticity are then discussed in the context of a structural difference between free-stream intermittency in the boundary layer and ‘quiescent core’ intermittency in the pipe that is detectable to wall distances as small as 5 % of the layer thickness.