煤量甏圆家重点实验宝 3. Reynolds time average equations with Reynolds average and assume PO=o po=po 2-6) )=(F。) National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn
NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn 3. Reynolds time average equations with Reynolds average and assume: ) ( ) i i x x = = = ( ' 0 (2-6)
煤烧圆家重点实验宝 (p)+-(m,小)=-( )-(pv)+S (2-7 p=1,v1,y,h S,=0 ap +g+-(-),W O National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn
NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn v S x x x v t x j j j j j j + − = + ( ) ( ) ( ) ( ') ' (2-7) s r i j j i i i s w q x v x g x p S v Y h − − + + = − = 0, ( ), , 1, , ,
煤量甏圆家重点实验宝 Note: 1)in equation(2-7), the variables are averaged values 2)the new term comes from the Reynolds average of non-linear convection term termed turbulent transport flux of o. Just because of this term the number of un known variables is more than the independent equations National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn
NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn Note: 1) in equation (2-7), the variables are averaged values 2) the new term comes from the Reynolds average of non-linear convection term, termed turbulent transport flux of φ. Just because of this term, the number of unknown variables is more than the independent equations
煤量烧圆家重点实验宝 §2 TurbulentⅤ scouse Coefficient Models 1. Concept of turbulent viscousity For two-dimensional boundary layer Boussinesq( 1877) proposed au t=-p=1 t -Reynolds stress u- fluid velocity in main stream ut- turbulent viscosity coefficient Wuhan 430074 P.R. CHINA E-mail:pcbnlcc@hust.edu.cn
NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn §2 Turbulent Viscouse Coefficient Models 1. Concept of turbulent viscousity For two-dimensional boundary layer, Boussinnesq(1877) proposed y u u v t t = − ' ' = (2-8) t - Reynolds stress u - fluid velocity in main stream t - turbulent viscosity coefficient
煤量甏圆家重点实验宝 In general Ov OVv=u, )-m水O Ox 3 p=()(=Y,h o ax Where k- time averaged value of turbulent kinetic energy of unit volume of fluid (2) 2-9) National Lab, of Coal Combustion. HUST Wuhan 430074 P R CHINA E-mail:pcbnlcc@hust.edu.cn
NL CC National Lab. of Coal Combustion, HUST Wuhan 430074, P. R. CHINA E-mail: pcbnlcc@hust.edu.cn In general, ' ' ( ) 3 2 ( ) ' ' j t j i j j i i j j i t x v k x v x v v v − = − + − = ( Y ,h) = s Where k - time averaged value of turbulent kinetic energy of unit volume of fluid ( ) 2 1 '2 k vi (2-9)