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Abstract Slowly evolving stratified flow over rough topography is subject to substantial drag due to internal motions, but often numerical simulations are carried out at resolutions where this “wave” drag must be parameterized. Here we highlight the importance of internal drag from topography with scales that cannot radiate internal waves, but may be highly nonlinear, and we propose a simple parameterization of this drag that has a minimum of fit parameters compared to existing schemes. The parameterization smoothly transitions from a quadratic drag law () for lowNh/u0(linear wave dynamics) to a linear drag law () for highNh/u0flows (nonlinear blocking and hydraulic dynamics), whereNis the stratification,his the height of the topography, andu0is the near-bottom velocity; the parameterization does not have a dependence on Coriolis frequency. Simulations carried out in a channel with synthetic bathymetry and steady body forcing indicate that this parameterization accurately predicts drag across a broad range of forcing parameters when the effect of reduced near-bottom mixing is taken into account by reducing the effective height of the topography. The parameterization is also tested in simulations of wind-driven channel flows that generate mesoscale eddy fields, a setup where the downstream transport is sensitive to the bottom drag parameterization and its effect on the eddies. In these simulations, the parameterization replicates the effect of rough bathymetry on the eddies. If extrapolated globally, the subinertial topographic scales can account for 2.7 TW of work done on the low-frequency circulation, an important sink that is redistributed to mixing in the open ocean.
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Dynamic Effects in Intramolecular Schmidt Reactions: Entropy, Electrostatic Drag, and Selectivity Prediction
Abstract Electrostatic drag in the intramolecular Schmidt reactions of azidopropylcyclohexanones is characterized using density functional theory (DFT) calculations and direct dynamics simulations. Despite resulting from enthalpically favorable interactions, electrostatic drag slows down N2loss during formation of bridged lactam products, an effect with implications for controlling product selectivity.
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- Award ID(s):
- 1856416
- PAR ID:
- 10257547
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemPhysChem
- Volume:
- 22
- Issue:
- 7
- ISSN:
- 1439-4235
- Format(s):
- Medium: X Size: p. 649-656
- Size(s):
- p. 649-656
- Sponsoring Org:
- National Science Foundation
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