ST_wset.m 1.8 KB
 Pierre Cazenave committed Jun 20, 2012 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 ``````function [wset] = ST_wset(d,varargin) % Calculate settling velocity of particle diameter d (m) in m/s % % function [wset] = ST_wset(d,varargin) % % DESCRIPTION: % Calculate settling velocity of particle diameter d (m) in m/s % % INPUT: % d: sediment grain size in m % [optional] 'temperature' = temperature of the seawater in C [default=10] % [optional] 'salinity' = salinity of seawater in PSU [default=35] % [optional] 'sdens' = sediment density in kg/m^3 [default=2650] % % OUTPUT: % wset: settling velocity in m/s % % EXAMPLE USAGE % wset = ST_wset(.0005,'temperature',10,'salinity',35,'sdens',2650) % % Author(s): % Geoff Cowles (University of Massachusetts Dartmouth) % % References % Soulsby DMS (102) % % Revision history % %============================================================================== subname = 'ST_wset'; %fprintf('\n') %fprintf(['begin : ' subname '\n']) % constants grav = 9.8106; %g T = 10; %T (C) S = 35; %S (PSU) sdens = 2650; %sediment density in kg/m^3 % parse arguments for i=1:2:length(varargin)-1 keyword = lower(varargin{i}); if( ~ischar(keyword) ) error('incorrect usage of ST_wset') end; switch(keyword(1:3)) case 'tem' T = varargin{i+1}; case 'sal' S = varargin{i+1}; case 'sde' sdens = varargin{i+1}; otherwise error(['Can''t understand value for:' keyword]); end; %switch keyword end; % calculate nu nu = SW_Kviscosity(T,S); % calculate rho dens = SW_Density(T,S); %dens/1000. % calculate dstar dstar = ST_Dstar(d,'temp',T,'sal',S,'sdens',sdens); % calculate wset wset = (nu/d)*( sqrt(10.36^2 + 1.049*(dstar^3)) - 10.36); %fprintf(['end : ' subname '\n'])``````