Modul kuliah mekflud 1

MEKANIKA FLUIDA (TEP201) • Dr. Ir. Erizal, MAgr. • Dr. Ir. Ir. Nora Nora Herdia Herdiana na Pan Panjai jaitan tan,, DEA. • Dr. Ir. Yuli Suharnoto • Dr Dr.. Ir Ir.. Ro Roh h Sa Sant ntos oso o

Depart Depa rtem emen en Te Tekn knik ik Pe Pert rtan ania ian n Faku Fa kult ltas as Te Tekn knol olog og Pe Pert rtan ania ian n Inst In stit itut ut Pe Pert rtan ania ian n Bo Bogo gorr

TEP201 Fluid Mechanics

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MEKANIKA FLUIDA



Mempelajari tentang fluida yang bergerak atau diam dan akibat yang ditimbulkan oleh fluida tersebut pada tempatnya.


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Tu j u a n I ns n s t r u k si sional Um u m • Setelah menyelesaikan mata kuliah ini, mahasiswa diharapkan mampu meng me ngur urai aika kan n ka kara rakt kter eris isti tik k fl flui uida da bai baik k dalam keadaan diam maupun bergerak dalam kaitannya dengan kegiatan perenc per encana anaan an,, pen pengel gelol olaa aan n dan perancangan


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JADWAL KULIAH Selasa Sel asa 07. 07.00 00-08 -08.40 .40 / Rab Rabu u 15. 15.0000-16. 16.40 40 No. 1 2-3 4-5 6 7 8-9 10-11 12 13 14-15 16

Pokok Bahasan

Pendahuluan Fluida Statik Konsep aliran fluida Aliran fluida ideal Aliran fluida kompresibel

Pengajar Erizal Erizal Yuli Suharnoto Yuli Suharnoto Nora Panjaitan

UTS Aliran fluida nyata di dalam pipa Mesin-mesin fluida Teori lapisan batas Aliran fluida pada saluran terbuka Analisis dimensi dan similitude

Nora Panjaitan Roh Santoso Erizal Roh Santoso Yuli Suharnoto

Sebagian bahan kuliah dapat diambil di: http://web.ipb.ac.id/~erizal/mekflud/ TEP201 Fluid Mechanics

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JADWAL PRAKTIKUM No. 1 2 3 4 5 6 7 8 9 10 11

Topik Pendahuluan Bilangan Reynold Penentuan koefisien Orifice dan Venturi Head loss karena gesekan Head loss karena perubahan diameter pipa Head loss karena belokan dan katup Pengukuran debit aliran udara di pipa Pengukuran debit aliran di saluran terbuka Aliran kritis Lompatan hidrolik Ujian praktikum


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PRAKTIKUM 1. Mahasiswa harap hadir paling lambat 5 menit sebelum praktikum dimulai di Laboratorium Hidrolika dan Hidromekanika Departemen Teknik Pertanian (F-G204). 2. Pr Prak akti tiku kum m di dila laks ksan anak akan an 4 ka kali li dal dalam am 1 ming minggu gu (S (Sel elas asa, a, Rab Rabu, u, Kam Kamis is,, da dan n Ju Jum’ m’at at). ). 3. Pe Pela laks ksan anaa aan n pr prak akti tiku kum m se seca cara ra ke kelo lompo mpok/ k/gr grup up ya yang ng te terd rdir irii at atas as 66-7 7 ma maha hasi sisw swa. a. 4. Perta Pertanyaan nyaan sebelum sebelum praktikum praktikum wajib dijawab dan diserahkan diserahkan kepada dosen/a dosen/asiste sisten n dosen. 5. Praktikum harus selalu dihadiri. Jika berhalangan harus mendapatkan surat izin dari departemen. 6. Setela Setelah h praktik praktikum um dilaks dilaksanakan anakan,, buatlah buatlah lapora laporan n sementa sementara ra berisi data hasil pengukuran yang dilengkapi dengan daftar anggota grup/kelompok. 7. La Lapo pora ran n pe pers rseo eora rang ngan an da dan n di ditu tuli liss de deng ngan an ta tang ngan an pa pada da ke kert rtas as uk ukur uran an A4 A4,, ke kemu mudi dian an peny pe nyer erah ahan anny nya a pa pali ling ng la lamb mbat at se sebe belu lum m pr prak akti tiku kum m di dimu mula laii pa pada da mi ming nggu gu be beri riku kutn tnya ya.. 8. Laporan berisi : • • • • •

Pendah Pend ahul ulua uan n ya yang ng beri berisi si te teor orii si sing ngka katt da dan n tujua tujuan n pra prakt ktik ikum um Bahan Bah an dan Me Metod tode e Hasil Ha sil dan Pembah Pembahasa asan n Kesimpula Kesi mpulan n dan Sara Saran n Dafta Da ftarr Pus Pusta taka ka

9. Segala bentuk pelanggaran dapat diberikan sanksi akademik berupa : skorsing prakti pra ktikum kum,, tidak tidak dipe diperke rkenan nankan kan meng mengiku ikuti ti uji ujian, an, dan dan lain sebaga sebagainy inya. a. 10. Pa Pada da ak akhi hirr sem emes estter akan akan di diad adak akan an uj ujia ian n pr prak akttik ikum um ol oleh eh do dossen en..


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PENILAIAN & PUSTAKA • • •

Praktikum : 30% UTS : 30% Ujian Ak Akhir : 40% Streeter, V.L. dan E.B. Wylie. Wylie. 1999. Mekanika Fluida. Penerbit Penerbit Erlangga. Jakarta. Giles, Ranald, V. 1994. Fluid Mechanics and Hydraulics. Schaum’s Outline Series. McGraw Hill Book Co. New York Hughes, W.F dan J.A. Brighton. 1967. Theory and Problem of Fluid Dynamic. Schaum’s Outline Series. McGraw Hill Book Co. New York Vennard, J.K dan R.L. Street. 1976. Elementary Fluid Mechanics. John Wiley and Sons. New York Erizal dan Panjaitan, N.H. 2007. Pedoman Praktikum Mekanika Fluida. IPB.


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Introduction to Fluid Mechanics* Fred Stern, Stern, Tao Tao Xing, Xing, Jun Shao, Shao, Suraje Surajeet et Ghos Ghosh h AFD

EFD

CFD

(Analytical Fluid Dynamics)

(Experimental (Experimen tal Fluid Dynamics)

(Computational Fluid Dynamics)

∇•U = 0 DU Dt

= −∇ +

1 2 p ∇ U +∇• Re

i

j

uu

*Revised version of 4/99 by Fred Stern and Eric Paterson TEP201 Fluid Mechanics

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Fluid Mechanics • Fluids essential to life • Human body 95% water • Earth’s surface is 2/3 water • Atmosphere extends 17km above the earth’s surface

• History shaped by fluid mechanics • • • •

Geomorphology Human migration and civilization Modern scientific and mathematical theories and methods Warfare

• Touches every part of our lives


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History Faces of Fluid Mechanics

Archimedes

Newton

(C. 287-212 BC)

(1642-1727)

Navier (1785-1836)

Stokes (1819-1903)

Leibniz

Bernoulli

Euler

(1667-1748)

(1707-1783)

Reynolds

Prandtl

(1842-1912)

(1875-1953)

Taylor

(1646-1716)


(1886-1975) 10

Significance • Fluids omnipresent • Weather & climate • Vehicles: automobiles, trains, ships, and planes, etc. • Environment • Physiology and medicine • Sports & recreation • Many other examples!


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Weather & Climate Tornadoes

Thunderstorm

Global Climate

Hurricanes


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Vehicles Surface ships

Aircraft

High-speed rail


Submarines

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Environment Air pollution


River hydraulics

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Physiology and Medicine Blood pump

Ventricular assist device


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Sports & Recreation Water sports

Cycling

Auto racing

Offshore racing

Surfing


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Fluids Engineering • Engineers have different kinds of tools available for solving fluids engineering systems • Analytical Fluid Dynamics (AFD) • Experimental Fluid Dynamics (EFD) • Computational Fluid Dynamics (CFD)

• This class provides an introduction to all three tools: AFD through lecture and CFD and EFD through labs


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Analytical Fluid Dynamics • The theory of mathematical physics problem formulation • Control volume & differential analysis • Exact solutions only exist for simple geometry and conditions • Approximate solutions for practical applications • Linear • Empirical relations using EFD data


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Analytical Fluid Dynamics •

Lecture Part of Fluid Class • • • • • • • •

Definition and fluids properties Fluid statics Fluids in motion Continuity, momentum, and energy principles Dimensional analysis and similitude Surface resistance Flow in conduits Drag and lift


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Analytical Fluid Dynamics • Example: laminar pipe flow

ρUD < 2000 Assumptions: Fully developed, Low Re = Approach:: Simplify momentum equation, μ Approach Schematic integrate, apply boundary conditions (noslip wall) to determine integration constants and use energy equation to calculate head loss 0 0 ⎡ ∂ 2u ∂ 2u ⎤ Du 0 ∂ p =− + μ ⎢ 2 + 2 ⎥ + g x ∂ x ∂ y ⎦ Dt ⎣ ∂ x Exact solution :

u(r) = 1 (− ∂ p )(R2 − r 2) 4μ ∂ x

Friction factor: f = Head loss:

p1 γ

+

8τ w = 2 ρV

z= 1

p2 γ

+

8μ du dy

w

ρ V 2

z2 + hf

= 64

Re h f

=

2

f

LV

D2 g


=

32 μ LV 2

γ D

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Analytical Fluid Dynamics • Example: turbulent flow in smooth pipe( Re > 3000) Three layer concept (using dimensional analysis)

u+ 1.

u*

y+ = yu ν

*

*

=

τ w ρ

+

= y+

0 < y

+

<5

Over Ov erlap lap la laye yerr (vis (visco cous us an and d tur turbu bule lent nt sh shea earr imp impor orta tant) nt) u

+

=

1 κ

3.

u

Lami La mina narr sub sub-l -lay ayer er (v (vis isco cous us sh shea earr dom domin inat ates es)) u

2.

=u

ln y +

+B

20 < y +

< 105

(=0.41, B=5.5)

Outer layer (turbulent shear dominates)

Assume log-law is valid across entire pipe:

U

−u u

u (r ) u

*

*

=

⎛ r ⎞ = f ⎜ 1 − ⎟ ⎝ r 0 ⎠ 1 κ

ln

y

( r0 − r )u *

+

> 10 5

+ B

ν

Integration for average velocity and using EFD data to adjust constants: 1 f

R e f 1 2 ) − .8 = 2 log ( Re


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Analytical Fluid Dynamics • Example: turbulent flow in rough pipe Both laminar laminar sublaye sublayerr and overlap overlap layer layer are affected by roughness Inner layer: u + = u + y k

(

)

Outer layer: unaffected u

Overlap layer:

+

=

1 κ

ln

y k

+ constant

Three reg Three regime imess of fl flow ow dep depen endin ding g on k + 1. K +<5, hydraulically smooth (no effect of roughness) 2. 5 < K+ < 70, transitional roughness (Re dependent) 3. K +> 70, fully rough (independent Re)

For 3, using EFD data to adjust constants: u

+

=

1 κ

ln

y k

+ 8.5 ≠ f ( Re )

Friction factor:


1 f

= −2log

k D

3.7

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Analytical Fluid Dynamics • Example: Moody diagram for turbulent pipe flow Composite Log-Law for smooth and rough pipes is given by the Moody diagram:

1 f

1

2

⎡ k D 2.51 ⎤ = −2log ⎢ + ⎥ 3 . 7 Re f 1 2 ⎦ ⎣


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Experimental Fluid Dynamics (EFD) Definition: Use of experimental methodology and procedures for solving fluids engineering systems, including full and model scales, large and table top facilities, measurement systems (instrumentation, data acquisition and data reduction), uncertainty analysis, and dimensional analysis and similarity. EFD philosophy: • Decisions on conducting experiments are governed by the ability of the expected test outcome, to achieve the test objectives within allowable uncertainties. • Integration of UA into all test phases should be a key part of entire experimental program • test design • determination of error sources • estimation of uncertainty • documentation of the results


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Purpose • Science & Technology: understand and investigate a phenomenon/process, substantiate and validate a theory (hypothesis)

• Research & Development: document a process/system, provide benchmark data (standard procedures, validations), calibrate instruments, equipment, and facilities • Industry: design optimization and analysis, provide data for direct use, product liability, and acceptance • Teaching: instruction/demonstration


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Applications of EFD

Application in science & technology

Application in research & development

Picture Pict ure of Karman Karman vorte vortex x shedding shedding

Tropic Wind Tunnel has the ability to create temperatures ranging from 0 to 165 degrees Fahrenheit and simulate rain


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Applications of EFD (cont’d)

Example of industrial application NASA's cryogenic wind tunnel simulates flight conditions for scale models--a critical tool in designing airplanes. Application in teaching Fluid dynamics laboratory TEP201 Fluid Mechanics

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Full and model scale

• Scales: model, and full-scale • Selection of the model scale: governed by dimensional analysis and similarity


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Measurement systems • Instrumentation • • • • •

Load cell to measure forces and moments Pressure transducers Pittot tub Pi ube es Hotwire anemometry PIV, LDV

• Data acquisition • • • •

Serial port devices Desktop PC’s Plug-in data acquisition boards DA sof softwa tware re - Lab Labvie view w

• Data analysis and data reduction • Data reduction equations • Fast Fourier Transform


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Instrumentation

Pit itot ot tu tub be

Load cell

3D - PIV

Hotwire TEP201 Fluid Mechanics

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Data acquisition system Hardware

Softwa Sof tware re - La Labvi bview ew


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Modul kuliah mekflud 1

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