Mixing in Cold water Domes and at Sills

  • Slides: 25
Download presentation
Mixing in Cold water Domes and at Sills Alan M. Davies and Jiuxing Xing

Mixing in Cold water Domes and at Sills Alan M. Davies and Jiuxing Xing Proudman Oceanographic Laboratory, Liverpool, UK

Dome Problem • Wind forced internal waves in cold water bottom dome. • Mixing

Dome Problem • Wind forced internal waves in cold water bottom dome. • Mixing within thermocline. Internal mixing. • Role of Vorticity at dome front in producing internal wave • Role of wind forcing frequency. Super and Sub- inertial features

Non-Linear effects on Inertial Oscillations • Unbounded Ocean Eqts • Effect of external shear

Non-Linear effects on Inertial Oscillations • Unbounded Ocean Eqts • Effect of external shear is to change Amp. + Freq. of I. O. • Frontal Shear Changes I. O. amp. /Freq at depth so conv/divg. Gives internal wave at level of thermocline. • Freq. int. wave above inertial propogates away , if below trapped

Super-inertial wind forcing

Super-inertial wind forcing

• Wavelength λf from Dispersion Relation • ωf = forcing frequency • So

• Wavelength λf from Dispersion Relation • ωf = forcing frequency • So λf/Leff gives nodal structure where Leff is “effective length” of dome

Sub-inertial wind forcing

Sub-inertial wind forcing

CONCLUSIONS • 1. Non-linear effects associated with along frontal flows produce near-inertial internal waves

CONCLUSIONS • 1. Non-linear effects associated with along frontal flows produce near-inertial internal waves in presence of wind forcing • 2. Super-inertial internal waves propagate away from generation region (front) • 3. Sub-inertial are trapped and enhance mixing in frontal region • 4. In a cold water bottom dome, super-inertial internal waves are trapped as standing waves, can modify GM spectrum • 5. Response in centre of dome different from 1 D model, must account for internal wave • 6. Sub-inertial wave confined to front, and response in centre of dome as in 1 D model

TIDAL MIXING AT SILLS • • • Idealized Loch Etive Recent measurements Inall et

TIDAL MIXING AT SILLS • • • Idealized Loch Etive Recent measurements Inall et al Non-hydrostatic model High resolution Idealized M 2 forcing + idealized T profile Example of internal mixing of tidal origin

Initial Conditions

Initial Conditions

Influence of small scale topog. • Lee wave characteristics influenced by • Buoyancy frequency

Influence of small scale topog. • Lee wave characteristics influenced by • Buoyancy frequency • Velocity over sill…. . Froude Number • Fourier transform of topog. • So How small scale effect mixing ? ? ?

CONCLUSIONS…. . Sill • • Internal tide little mixing Lee Wave not advected back

CONCLUSIONS…. . Sill • • Internal tide little mixing Lee Wave not advected back over sill Lee Wave major source of mixing Lee wave distribution influenced by nonhydro. nature of model • Lee wave spectrum/mixing influenced by small scale topog. + Horizontal Visc. • Assumptions in b. b. l. also infulence lee wave hence mixing

Future • Role surface stratification / fresh water , wind mixing • Detailed distribution

Future • Role surface stratification / fresh water , wind mixing • Detailed distribution of Topog. • Sill b. b. l effects • Lateral + across sill form drag • Horizontal + Vertical tke schemes (LES) • Role non-linearity (u du/dx ) Internal tides vz. Lee waves control on mixing

Model Skill Assessment • Model Validation in highly variable undersampled domain. • Spectral Decompostion.

Model Skill Assessment • Model Validation in highly variable undersampled domain. • Spectral Decompostion. . Hans van Haren • Detailed measurement critical small scale topog. and stratification. • Tidal corrected dissipation rates and mixing + filtered lee wave advection effects • Role of lab. Expts + upscale.

Mixing and Homogenization Definition of mixing Mixing mayMixing and Homogenization Definition of mixing Mixing may
Domes Domes are curved structures with no anglesDomes Domes are curved structures with no angles
MIXING MODELS AND ENDMEMBER MIXING ANALYSIS PRINCIPLES ANDMIXING MODELS AND ENDMEMBER MIXING ANALYSIS PRINCIPLES AND
Mixing Warm and Cold Water Collecting Data usingMixing Warm and Cold Water Collecting Data using
Basalts fine grained volcanic Dolerite sills and dykesBasalts fine grained volcanic Dolerite sills and dykes
CE 547 Mixing and Flocculation 1 Mixing IsCE 547 Mixing and Flocculation 1 Mixing Is
Color MIXING LIGHT Misconceptions and problems Mixing lightColor MIXING LIGHT Misconceptions and problems Mixing light
Code Mixing and Code Switching Code Mixing UsingCode Mixing and Code Switching Code Mixing Using
Mrs Sills 2 nd Grade Class 2019 2020Mrs Sills 2 nd Grade Class 2019 2020
2017 Hammmons Sills Adkins Guice LLP For Educational2017 Hammmons Sills Adkins Guice LLP For Educational
Diabetic Ketoacidosis Irene N Sills MD Albany MedicalDiabetic Ketoacidosis Irene N Sills MD Albany Medical
Precambrian olistoliths masquerading as sills from Death ValleyPrecambrian olistoliths masquerading as sills from Death Valley
Implementing the Dignity Challenge Eileen Sills CBE ChiefImplementing the Dignity Challenge Eileen Sills CBE Chief
Staff Wellness How to get Involved Stacey SillsStaff Wellness How to get Involved Stacey Sills
COOPCOMMUNITY CLASSROOM Mrs Sills Placement Specialist Holland PublicCOOPCOMMUNITY CLASSROOM Mrs Sills Placement Specialist Holland Public
Lagrangian Mixing John Elton Fluid mixing is aLagrangian Mixing John Elton Fluid mixing is a
Mixing questions mixing methods Carl May My researchMixing questions mixing methods Carl May My research
LECTURE 4 MIXING DEFINITION Mixing a process thatLECTURE 4 MIXING DEFINITION Mixing a process that
Mixing drinks A metacognitive activity Task 1 MixingMixing drinks A metacognitive activity Task 1 Mixing
ADDITIVE COLOUR MIXING SUBTRACTIVE COLOUR MIXING ADDITIVE COLOURADDITIVE COLOUR MIXING SUBTRACTIVE COLOUR MIXING ADDITIVE COLOUR
2 5 Mixing Problems Modeling Mixing Problems In2 5 Mixing Problems Modeling Mixing Problems In
MIXING CHARACTERISTICS OF MIXTURES 1 Mixing is theMIXING CHARACTERISTICS OF MIXTURES 1 Mixing is the
Plastic Compounding Mixing By mixing we mean bringingPlastic Compounding Mixing By mixing we mean bringing
Mixing Pesticides Most pesticide accidents occur during MixingMixing Pesticides Most pesticide accidents occur during Mixing