David H Richter

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A point-force model is used to study turbulent momentum transfer in the presence of moderate mass loadings of small (relative to Kolmogorov scales), dense (relative to the carrier phase density) particles. Turbulent Couette flow is simulated via direct numerical simulation, while individual particles are tracked as Lagrangian elements interacting with the(More)
The effect of initial microstructural deformation, alignment, and morphology on the response of wormlike micelle solutions in transient uniaxial extensional flows is investigated using a pre-shear device attached to a filament stretching rheometer. In filament stretching experiments, increasing the strength and the duration of the pre-shear just before(More)
Direct numerical simulations (DNS) of turbulent Couette flow are combined with Lagrangian point-particle tracking to investigate the effects of a dispersed phase on bulk passive heat transport when the two phases can exchange both momentum and sensible heat. The idealized setup allows a fixed number of particles, without the influence of gravity, to be(More)
[1] Motivated by the possible effects of spray on the drag felt by the ocean surface in high winds, we use direct numerical simulation coupled with Lagrangian particle tracking to investigate how suspended inertial particles alter momentum flux in an idealized turbulent flow. Turbulent Couette flow is used for this purpose since the momentum flux profile is(More)
Articles you may be interested in Large eddy simulations of Taylor-Couette-Poiseuille flows in a narrow-gap system A hybrid stochastic-deconvolution model for large-eddy simulation of particle-laden flow A unified probability density function formulation to model turbulence modification in two-phase flow Characterization of near-wall turbulence in terms of(More)
At Re = 3900, Newtonian flow past a circular cylinder exhibits a wake and detached shear layers which have transitioned to turbulence. It is the goal of the present study to investigate the effects which viscoelasticity has on this state and to identify the mechanisms responsible for wake stabilization. It is found through numerical simulations (employing(More)
Direct numerical simulations are performed of turbulent planar Couette flow which are seeded with two-way coupled particles at low volume concentration. Based on an understanding of the development of particle stress (horizontal momentum carried vertically on average by the particle phase) in monodisperse systems at various particle Stokes numbers, several(More)
Direct numerical simulations of an Eulerian-based carrier phase are performed which are two-way coupled in momentum and energy to Lagrangian droplets within a Boussinesq-type incompressible formulation, where the droplets are allowed to evaporate and condense and are thus coupled to the vapor field of the carrier phase. Turbulent planar Couette flow is(More)
Key Points: • Spray dominates enthalpy flux at the hurricane air-sea interface • Enthalpy fluxes can be estimated from dropsonde thermodynamic data • Trends of enthalpy flux coefficient can be misleading due to uncertainty Evidence of spray-mediated air-sea enthalpy flux within tropical cyclones, Abstract It has long been conjectured that spray ejected from(More)