55 lines
1.0 KiB
Matlab
55 lines
1.0 KiB
Matlab
%-------------------------------------%
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% Figure of the Laplacian Dissipation %
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%-------------------------------------%
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nx = 64;
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dt = 1;
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%--- polynomical of small-scale dissipation
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rsig = [64];
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nsig2 = [2];
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nsig3 = [3];
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tsigm1 = [0.1]; % tsig^(-1) in units of dt
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%--- polynomical of large-scale dissipation
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rlam = [1];
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nlam = [1];
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tlamm1 = [0.01]; % tlam^{-1} in units of dt
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%--- wave number grid
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kx = fix(nx/3);
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%============== internal part ============
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%--- spectral grid
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k = 0:0.1:kx;
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rk = k;
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D_nsig2 = (rk./rsig).^(2*(nsig2-1));
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D_nsig3 = (rk./rsig).^(2*(nsig3-1));
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D_lamn = (rk./rlam).^(-2*nlam);
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expDnsig2 = exp(-D_nsig2*(dt*tsigm1));
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expDnsig3 = exp(-D_nsig3*(dt*tsigm1));
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expDlamn = exp(-D_lamn*(dt*tlamm1));
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ff = figure
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ax = axes
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set(ax,'FontSize',[16]);
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set(ax,'FontWeight','bold');
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set(ax,'XLim',[0,kx]);
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set(ax,'YLim',[0.9,1]);
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hold
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grid on
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pp1 = plot(rk,expDnsig2,'k');
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set(pp1,'LineWidth',[2]);
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pp2 = plot(rk,expDlamn,'k--');
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set(pp2,'LineWidth',[2]);
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pp3 = plot(rk,expDnsig3,'r');
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set(pp1,'LineWidth',[2]);
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