1.0 OBJECT OBJECTIVE IVE
1.1 To observe the laminar, transitional and turbulent flow. 1.2 To compute Reynolds number (R).
2.0 INTROD INTRODUCT UCTION ION
The SOT!"# Osborne Reynold$s %emonstration (&odel' & 11) has been desined for studen students ts e*peri e*perimen mentt on the lamina laminar, r, transi transiti tion on and turbul turbulent ent flow. flow. +t consis consists ts of a transparent header tan and flow visuali-ation pipe. The header tan is provided with a diffuser and stillin materials at the bottom to provide a constant head of water to be dischared throuh a bell mouth entry to the flow visuali-ation pipe. low throuh this pipe is reulated usin a control valve at the dischare end. The water flow rate throuh the pipe can be measured usin the volumetric tan (or volumetric cylinder). elocity of the water can therefore be determined to allow the calculation of the Reynold$s /umber. 0 dye inection system is installed on top of the header tan so that flow pattern in the pipe can be visuali-ed.
3.0 THEORY
The theory is named in honor of Osborne Reynolds, a ritish enineer who discovers the variables that can be used as a criterion to distinuish between laminar and turbulent flow. The Reynolds number is widely used dimensionless parameters in fluid mechanics. Reynolds number formula'
R 3 Reynolds number 3 luid velocity, (m4s) 3 characteristic lenth or diameter d iameter (m) 3 5inematic viscosity (m24s) Reynolds number R is independent of pressure
3.1 Pipe Flow Condition
or water flowin in pipe or circular conduits, is the diameter of the pipe. or Reynolds number less than 2166, the pipe flow will be laminar. or Reynolds number from 2166 to 7666 the pipe flow will be considered a transitional flow. Turbulent occur when Reynolds number is above 7666. The viscosity of the fluid also determines the characteristic of the flow becomin laminar or turbulent. luid with hiher viscosity is easier to achieve a turbulent flow condition. The viscosity of fluid is also dependant on the temperature. 3.2 !"#in"$ Flow
aminar flow denoted a steady flow condition where all streamlines follow parallel paths, there bein no interaction (mi*in) between shear planes. 8nder this condition the dye observed will remain as a solid, straiht and easily identifiable component of flow. 3.3 T$"nition"l Flow
Transitional flow is a mi*ture of laminar and turbulent flow with turbulence in the center of the pipe, and laminar flow near the edes. !ach of these flows behaves in different manners in terms of their frictional enery loss while flowin, and have different e9uations that predict their behavior. 3.% T&$'&lent Flow
Turbulent flow denotes an unsteady flow condition where streamlines interact causin shear plane collapse and mi*in of the fluid. +n this condition the dye observed will become disperse in the water and mi* with the water. The observed dye will not be identifiable at this point.
%.0 E(UIP)ENT*
1. %ye reservoir :. Stillin tan ;.
.
2. %ye inector 7. Observation tube =. ell mouth ?. Overflow tube
Observation tube diameter 3 1;.= mm
+.0 E,PERI)ENT-! PROCEDURE*
+.1 Epe$i#ent 1
Obectives' @ To compute Reynolds number (R). @ To observe the laminar, transitional and turbulent flow. Arocedures' 1. The water inlet and outlet valve were reulated to achieve a laminar flow. 2. The flow rate was measured. :. The e*periment was repeated for transitional and turbulent flow.
+.2 Epe$i#ent 2
Obectives' @ To determine the Reynolds number @ To determine the upper and lower critical velocities at transitional flow. Arocedures' 1.0 laminar flow was created, slowly the flow rate was increased until the laminar flow produced small disturbance or eddies. This will be lower critical velocity. 2. The flow rate was determined. :. The e*periment was repeated by first introducin a turbulent flow and slowly flow rate was decreased until the flow become transitional. This will be upper critical velocity.
/.0 RE*U!T* -ND C-!CU-!TION*
1. Aresents all your data in the form of T"'le -. 2. Show your calculations.
.0 (UE*TION*
1.
.0 CONC!U*ION*
1. erify your results. %o the Reynold$s numbers you calculate from your e*periments in the rane for each flowB
.0 -PPENDI,
T"'le -
Repeat for all flows.
