Spatially-averaged flows over mobile rough beds

TY - JOUR

T1 - Spatially-averaged flows over mobile rough beds

T2 - equations for the second-order velocity moments

AU - Papadopoulos, Konstantinos

AU - Nikora, Vladimir

AU - Cameron, Stuart

AU - Stewart, Mark

AU - Gibbins, Christopher

N1 - This study was part of the research project ‘Hydrodynamic Transport in Ecologically Critical Heterogeneous interfaces’ (HYTECH), the support of which, under the European Union’s Seventh Framework Programme (Marie Curie Actions FP7PEOPLE-2012-ITN, European Commission [grant agreement number 316546]),is gratefully acknowledged. Financial support was also provided by the Engineering and Physical Sciences Research Council (EPSRC)/UK grant “Bed friction in roughbed free-surface flows: a theoretical framework, roughness regimes, and quantification” [grant EP/K041088/1].

PY - 2019/1/18

Y1 - 2019/1/18

N2 - The double-averaging methodology is used in this paper for deriving equations for the second-order velocity moments (i.e. turbulent and dispersive stresses) that emerge in the double-averaged momentum equation for incompressible Newtonian flows over mobile boundaries. The starting point in the derivation is the mass and momentum conservation equations for local (at a point) instantaneous variables that are up-scaled by employing temporal and spatial averaging. First, time-averaged conservation equations for mass, momentum, and turbulent stresses for mobile bed conditions are derived. Then, the double-averaged hydrodynamic equations obtained by spatial averaging the time-averaged equations are proposed. The derived second-order equations can serve as a basis for the construction of simplified mathematical and numerical models and for interpretation of experimental and simulation data when bed mobility is present. Potential applications include complex flow situations such as free-surface flows over vegetated or mobile sedimentary beds and flows through tidal and wind turbine arrays.

AB - The double-averaging methodology is used in this paper for deriving equations for the second-order velocity moments (i.e. turbulent and dispersive stresses) that emerge in the double-averaged momentum equation for incompressible Newtonian flows over mobile boundaries. The starting point in the derivation is the mass and momentum conservation equations for local (at a point) instantaneous variables that are up-scaled by employing temporal and spatial averaging. First, time-averaged conservation equations for mass, momentum, and turbulent stresses for mobile bed conditions are derived. Then, the double-averaged hydrodynamic equations obtained by spatial averaging the time-averaged equations are proposed. The derived second-order equations can serve as a basis for the construction of simplified mathematical and numerical models and for interpretation of experimental and simulation data when bed mobility is present. Potential applications include complex flow situations such as free-surface flows over vegetated or mobile sedimentary beds and flows through tidal and wind turbine arrays.

KW - double averaging methodology

KW - form-induced stress

KW - mobile-boundary flows

KW - second-order hydrodynamic equations

KW - spatially-averaged turbulent stress

KW - turbulence

KW - Double averaging methodology

UR - http://www.mendeley.com/research/spatiallyaveraged-flows-mobile-rough-beds-equations-secondorder-velocity-moments

UR - https://abdn.pure.elsevier.com/en/en/researchoutput/spatiallyaveraged-flows-over-mobile-rough-beds(0b7cc8f2-5c7a-41c9-b9c0-d4172e60202c).html

U2 - 10.1080/00221686.2018.1555559

DO - 10.1080/00221686.2018.1555559

M3 - Article

SP - 1

EP - 19

JO - Journal of Hydraulic Research

JF - Journal of Hydraulic Research

SN - 0022-1686

ER -