30P30N多段翼流場計算報告

qiangsu5961

2019年4月2日 17:17

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來源：陸面體科技。

1. 30P30N多段翼

增升裝置對于提高現代大型運輸類飛機性能十分重要。高效的增升裝置可以增加載重和航程、減輕飛機重量等。高升力機翼構型一般由翼身、前緣縫翼和后緣襟翼組成。在高速條件下，多段翼流場中可能存在轉捩、分離、激波/邊界層干擾等復雜流動現象。本文以30P30N多段翼為測試算例，檢驗SU2對于二維復雜外形的模擬能力。

30P30N多段翼流場計算報告的圖1 圖1：30P30N多段翼外形

30P30N多段翼流場計算報告的圖2

圖2：多段翼流動特征

2. 計算網格

表130P30N多段翼網格參數

網格構型	網格單元數
L1	63957
L2	112474
L3	260909
L4	583226
L5	1043636

網格采用JAXA提供的結構化網格(https://cfdws.chofu.jaxa. jp/apc/grids/3element_highlift_airfoil/30P30N_modified_slat_configF/plot3d/)。該網站提供了L1-L5等不同網格密度的五種結構化網格，這些網格具有相同的拓撲結構，都是由117塊網格塊構成，具體參數見表1。受計算資源限制，本文將對前4種網格進行網格無關性研究。該多段翼機翼弦長0.4572 m（18 inch），前緣逢翼和后緣襟翼均偏轉30°。

30P30N多段翼流場計算報告的圖3

30P30N多段翼流場計算報告的圖4

圖3：30P30N多段翼拓撲結構及網格

3.SU2求解器設置

下面以馬赫數為0.20、攻角為16°、湍流模型為SA的計算工況為例，介紹30P30N算例的cfg文件參數設置。

（1）問題定義

% ------------- DIRECT, ADJOINT, AND LINEARIZED PROBLEM DEFINITION ------------%

% Physical governing equations (EULER, NAVIER_STOKES,

% WAVE_EQUATION, HEAT_EQUATION, FEM_ELASTICITY,

% POISSON_EQUATION)

PHYSICAL_PROBLEM= NAVIER_STOKES

% Specify turbulent model (NONE, SA, SA_NEG, SST)

KIND_TURB_MODEL= SST

% Mathematical problem (DIRECT, CONTINUOUS_ADJOINT)

MATH_PROBLEM= DIRECT

% Restart solution (NO, YES)

RESTART_SOL= NO

（2）自由來流參數設置

% -------------------- COMPRESSIBLE FREE-STREAM DEFINITION --------------------%

% Mach number (non-dimensional, based on the free-stream values)

MACH_NUMBER= 0.2

% Angle of attack (degrees, only for compressible flows)

AOA= 16.0

% Free-stream temperature (288.15 K by default)

FREESTREAM_TEMPERATURE= 300

% Reynolds number (non-dimensional, based on the free-stream values)

REYNOLDS_NUMBER= 9.0E6

% Reynolds length (1 m by default)

REYNOLDS_LENGTH= 0.4572

（3）參考值設置

% ---------------------- REFERENCE VALUE DEFINITION ---------------------------%

% Reference origin for moment computation

REF_ORIGIN_MOMENT_X = 0.25

REF_ORIGIN_MOMENT_Y = 0.00

REF_ORIGIN_MOMENT_Z = 0.00

% Reference length for pitching, rolling, and yawing non-dimensional moment

REF_LENGTH= 1.0

% Reference area for force coefficients (0 implies automatic calculation)

REF_AREA= 0.4572

（4）邊界條件設置

% -------------------- BOUNDARY CONDITION DEFINITION --------------------------%

% Navier-Stokes wall boundary marker(s) (NONE = no marker)

MARKER_HEATFLUX= ( slat, 0.0, main, 0.0, flap, 0.0 )

% Farfield boundary marker(s) (NONE = no marker)

MARKER_FAR= ( far )

% Marker(s) of the surface to be plotted or designed

MARKER_PLOTTING= ( slat, main, flap )

% Marker(s) of the surface where the functional (Cd, Cl, etc.) will be evaluated

MARKER_MONITORING= ( slat, main, flap )

（5）數值求解通用參數

% ------------- COMMON PARAMETERS DEFINING THE NUMERICAL METHOD ---------------%

% Numerical method for spatial gradients (GREEN_GAUSS, WEIGHTED_LEAST_SQUARES)

NUM_METHOD_GRAD= WEIGHTED_LEAST_SQUARES

% Courant-Friedrichs-Lewy condition of the finest grid

CFL_NUMBER= 5

% Adaptive CFL number (NO, YES)

CFL_ADAPT= NO

% Parameters of the adaptive CFL number (factor down, factor up, CFL min value,

% CFL max value )

CFL_ADAPT_PARAM= ( 1.5, 0.5, 1.0, 100.0 )

% Number of total iterations

EXT_ITER= 99999

% Linear solver for the implicit formulation (BCGSTAB, FGMRES)

LINEAR_SOLVER= BCGSTAB

% Min error of the linear solver for the implicit formulation

LINEAR_SOLVER_ERROR= 1E-6

% Max number of iterations of the linear solver for the implicit formulation

LINEAR_SOLVER_ITER= 20

（6）多重網格參數

% -------------------------- MULTIGRID PARAMETERS -----------------------------%

% Multi-Grid Levels (0 = no multi-grid)

MGLEVEL= 0

% Multi-grid cycle (V_CYCLE, W_CYCLE, FULLMG_CYCLE)

MGCYCLE= W_CYCLE

% Multi-grid pre-smoothing level

MG_PRE_SMOOTH= ( 1, 2, 3, 3 )

% Multi-grid post-smoothing level

MG_POST_SMOOTH= ( 0, 0, 0, 0 )

% Jacobi implicit smoothing of the correction

MG_CORRECTION_SMOOTH= ( 0, 0, 0, 0 )

% Damping factor for the residual restriction

MG_DAMP_RESTRICTION= 0.95

% Damping factor for the correction prolongation

MG_DAMP_PROLONGATION= 0.95

（7）流場計算數值格式

% -------------------- FLOW NUMERICAL METHOD DEFINITION -----------------------%

% Convective numerical method (JST, LAX-FRIEDRICH, CUSP, ROE, AUSM, HLLC,

% TURKEL_PREC, MSW)

CONV_NUM_METHOD_FLOW= JST

% Monotonic Upwind Scheme for Conservation Laws (TVD) in the flow equations.

% Required for 2nd order upwind schemes (NO, YES)

MUSCL_FLOW= YES

% Slope limiter (VENKATAKRISHNAN, MINMOD)

SLOPE_LIMITER_FLOW= VENKATAKRISHNAN

% Coefficient for the limiter (smooth regions)

VENKAT_LIMITER_COEFF= 0.03

% 2nd and 4th order artificial dissipation coefficients

JST_SENSOR_COEFF= ( 0.5, 0.02 )

% Time discretization (RUNGE-KUTTA_EXPLICIT, EULER_IMPLICIT, EULER_EXPLICIT)

TIME_DISCRE_FLOW= EULER_IMPLICIT

（8）湍流計算數值格式

% -------------------- TURBULENT NUMERICAL METHOD DEFINITION ------------------%

% Convective numerical method (SCALAR_UPWIND)

CONV_NUM_METHOD_TURB= SCALAR_UPWIND

% Monotonic Upwind Scheme for Conservation Laws (TVD) in the turbulence equations.

% Required for 2nd order upwind schemes (NO, YES)

MUSCL_TURB= NO

% Time discretization (EULER_IMPLICIT)

TIME_DISCRE_TURB= EULER_IMPLICIT

（9）收斂準則

% --------------------------- CONVERGENCE PARAMETERS --------------------------%

% Convergence criteria (CAUCHY, RESIDUAL)

CONV_CRITERIA= RESIDUAL

% Residual reduction (order of magnitude with respect to the initial value)

RESIDUAL_REDUCTION= 10

% Min value of the residual (log10 of the residual)

RESIDUAL_MINVAL= -8

% Start convergence criteria at iteration number

STARTCONV_ITER= 10

% Number of elements to apply the criteria

CAUCHY_ELEMS= 100

% Epsilon to control the series convergence

CAUCHY_EPS= 1E-6

% Function to apply the criteria (LIFT, DRAG, NEARFIELD_PRESS, SENS_GEOMETRY,

% SENS_MACH, DELTA_LIFT, DELTA_DRAG)

CAUCHY_FUNC_FLOW= DRAG

（10）輸入輸出設置

% ------------------------- INPUT/OUTPUT INFORMATION --------------------------%

% Mesh input file

MESH_FILENAME= L1-30P30N.su2

% Mesh input file format (SU2, CGNS, NETCDF_ASCII)

MESH_FORMAT= SU2

% Mesh output file

MESH_OUT_FILENAME= mesh_out.su2

% Restart flow input file

SOLUTION_FLOW_FILENAME= restart_flow.dat

% Restart adjoint input file

SOLUTION_ADJ_FILENAME= solution_adj.dat

% Output file format (PARAVIEW, TECPLOT, STL)

OUTPUT_FORMAT= TECPLOT

% Output file convergence history (w/o extension)

CONV_FILENAME= history

% Output file restart flow

RESTART_FLOW_FILENAME= restart_flow.dat

% Output file restart adjoint

RESTART_ADJ_FILENAME= restart_adj.dat

% Output file flow (w/o extension) variables

VOLUME_FLOW_FILENAME= flow

% Output file adjoint (w/o extension) variables

VOLUME_ADJ_FILENAME= adjoint

% Output objective function gradient (using continuous adjoint)

GRAD_OBJFUNC_FILENAME= of_grad.dat

% Output file surface flow coefficient (w/o extension)

SURFACE_FLOW_FILENAME= surface_flow

% Output file surface adjoint coefficient (w/o extension)

SURFACE_ADJ_FILENAME= surface_adjoint

% Writing solution file frequency

WRT_SOL_FREQ= 250

% Writing convergence history frequency

WRT_CON_FREQ= 1

4.結果分析

4.1 湍流模型影響

30P30N多段翼流場計算報告的圖5

圖4：30P30N多段翼壓力分布SA和SST計算結果對比

圖4展示了SU2求解器分別采用SA模型和SST模型計算的30P30N多段翼表面壓力分布（Ma=0.20 AoA=16° Rec=9.0×10⁶）。可以看到，SA、SST模型計算的壓力分布在壓力面（迎風面、正壓區）與試驗結果符合較好，而在吸力面（背風面、負壓區）與試驗結果存在一定差異。兩種湍流模型相比，SA模型比SST模型更加接近試驗結果。

4.2 網格密度影響

30P30N多段翼流場計算報告的圖6

圖5：30P30N多段翼壓力分布不同網格密度計算結果對比

圖5展示了SU2求解器分別采用不同網格密度計算的30P30N多段翼表面壓力分布，湍流模型為SA模型。可以看到，隨著網格密度的增加，背風面負壓峰值不斷升高，也越來越接近試驗結果。該計算結果表明，30P30N多段翼算例對計算網格的密度較為敏感。采用L4網格和SA湍流模型計算的30P30N多段翼壓力分布與試驗結果基本符合。