Update as of 7/29/2014 Explanation of terms in the DNS data files: Unless otherwise stated, all variables are normalized by the initial channel half-width delta(0) and initial friction velocity u_tau(0). The initial conditions are based on the unstrained channel flow. (Data posted prior to 6/11/2014 were nondimensionalized differently: by initial channel half-width delta(0) and reference velocity Uref=26.330*utau(0).) Note that in the header section in each data file the variable u_tau provided is utau(t)/Uref. From the unstrained data, Re_tau(0) = RE*(u_tau(0)/u_ref)=391.68274815 Upper case U,V,W,P represent (unsteady, plane/cross-centerline/ensemble-averaged) mean values, and lower case u,v,w,p represent fluctuations strain_time = time over which the straining has been applied yw = wall-normal distance wrt delta(t), where delta(t)=delta(0)*exp(A22*t) A22 = uniform strain magnitude in wall-normal direction A11 = uniform streamwise deceleration (=-A22) (A13=A33=0 for this 2-D flow) B22 = exp(-A22*t) B11 = exp(-A11*t) B33 = exp(-A33*t) = 1 for this 2-D flow Ubar = mean streamwise velocity U dU/dy = partial derivative of U wrt y Wbar = mean spanwise velocity W (approx = 0 for this 2-D case) |dW/dy| = absolute value of partial derivative of W wrt y rms_u = root-mean-square of streamwise velocity fluctuations rms_v = root-mean-square of vertical velocity fluctuations rms_w = root-mean-square of spanwise velocity fluctuations .5*q2 = turbulent kinetic energy (TKE) = 0.5*(rms_u**2 + rms_v**2 + rms_w**2) -uv,-vw,|uw| = 2nd order turbulence velocity correlations = turbulent shear stress components tau_x = total (viscous plus turbulent) kinematic shear stress in the streamwise direction tau_x+ = tau_x in local (i.e., wrt utau(t)) wall units tau_z = total kinematic shear stress in the spanwise direction tau_z+ = tau_z in local wall units tau/q**2 = sqrt(uv(plane)**2+vw(plane)**2)/q2(plane) (Townsend structure parameter) |Pbar| = mean (i.e., the (k_x,k_z)=(0,0) mode) static kinematic pressure abs(P) wrt an arbitrary reference value |dP/dy| = absolute value of partial derivative of Pbar wrt y PP_bar = square of instantaneous pressure <(Pbar+p)(Pbar+p)> rms_p = root-mean-square of static kinematic pressure fluctuations Pk_Aii = production due to applied strain in the k-equation k^(3/2)/eps_k= turbulence length scale [k**(3/2)]/eps RE = Reynolds number with respect to ref velocity (Uref) and initial channel half-width (delta(0)) = 10313 S(u) = skewness of u S(v) = skewness of v S(w) = skewness of w S(p) = skewness of p F(u) = flatness of u F(v) = flatness of v F(w) = flatness of w F(p) = flatness of p p(s) = probability density function of s (these are given in separate pdf_*.dat files) uuv,uvv,vvv,uuu = 3rd order turbulence velocity correlations u3v,u2v2,uv3,v4,u4 = 4th order turbulence velocity correlations u4v,u3v2,u2v3,uv4,v5,u5,w5 = 5th order turbulence velocity correlations In the following, xx denotes term in particular budget; for example 22 for vv budget, 33 for ww budget, k for TKE budget (see also : Sciberras, M. A. and Coleman, G. N., "Testing of Reynolds-stress-transport closures by comparison with DNS of an idealized adverse-pressure-gradient boundary layer," European Journal of Mechanics B/Fluids, Vol. 26, 2007, pp. 551-582.). All terms are normalized by Uref**4/nu. For example, to convert the following to wall units wrt initial conditions, divide by (utau(0)/Uref)**4 = (1/26.330)**4: P_xx = production term \eps_xx = dissipation term T_xx = turbulent transport term D_xx = viscous diffusion term \Pi_xx = velocity pressure-gradient term Pxx_Axx = production terms due to applied straining d/dt = sum of RHS terms in transport equation ("balance" of the eqn) \phi_xx = pressure-strain term In the following, xxx denotes term in particular budget; for example 111 for uuu budget, 112 for uuv budget. All terms are normalized by Uref**5/nu. For example, to convert the following to wall units wrt initial conditions, divide by (utau(0)/Uref)**5 = (1/26.330)**5: PS_xxx = production term due to gradients of mean flow terms T_xxx = turbulent transport term D_xxx = viscous diffusion term PT_xxx = production term due to gradients of lower-order moment terms \Pi_xxx = velocity pressure-gradient term \eps_xxx = dissipation term PA_xxx = production term due to applied straining balance = sum of RHS terms in transport equation ("balance" of the eqn) \psi_xxx = pressure transport term In the following, xxxx denotes term in particular budget; for example 1111 for uuuu budget, 1112 for uuuv budget. All terms are normalized by Uref**6/nu. For example, to convert the following to wall units wrt initial conditions, divide by (utau(0)/Uref)**6 = (1/26.330)**6: PS_xxxx = production term due to gradients of mean flow terms T_xxxx = turbulent transport term D_xxxx = viscous diffusion term PT_xxxx = production term due to gradients of lower-order moment terms \Pi_xxxx = velocity pressure-gradient term \eps_xxxx = dissipation term PA_xxxx = production term due to applied straining balance = sum of RHS terms in transport equation ("balance" of the eqn) \psi_xxxx = pressure transport term Other turbulence velocity correlations provided: w3,w4,uw2,vw2,u2w2,v2w2,uvw2,u6,v6,w6 Other supplementary correlations provided: wdpdy,wdpdx,wdpdz,vdpdz,udpdz,w2dpdx,w2dpdy,uvdpdz,u2dpdz,v2dpdz,w2dpdz,ddy (where, for example, dpdz represents partial derivative of p wrt z, and ddy = partial derivative of correlation of w**2 wrt y) Changes between revisions: Changes between 6/11/2014 and 7/29/2014: 1. Pressure statistics were previously incorrect in all files (bug). 2. Minor differences in the unstrained data due to previous use of lower number of digits of accuracy in utau0 (used for non-dimensionalizing all quantities). 3. Minor differences in rms_p in unstrained data, due to revised method now consistent with how it was done for strained data. Changes between 5/19/2014 and 6/11/2014: 1. New data nondimensionalized by u_tau(0) rather than Uref=26.330*utau(0).