Simulasi Numerik Hemodinamika Stenosis Asimetris Pada Central Retinal Vein Occlusion (CRVO)

Putra, Juan Randy Christian (2026) Simulasi Numerik Hemodinamika Stenosis Asimetris Pada Central Retinal Vein Occlusion (CRVO). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Central Retinal Vein Occlusion (CRVO) merupakan gangguan aliran darah pada vena retina sentral yang dapat menyebabkan peningkatan hambatan aliran, perubahan tekanan lokal, edema retina, dan penurunan fungsi penglihatan. Penelitian ini mengkaji hemodinamika CRVO melalui simulasi numerik pada pembuluh vena retina yang mengalami stenosis asimetris dengan mempertimbangkan darah sebagai fluida non-Newtonian Casson. Geometri stenosis dibentuk dari kombinasi profil Overlapping, Cosine, dan Bell, yaitu Overlapping–Bell, Overlapping–Cosine, dan Cosine–Bell, dengan variasi ketebalan 35%, 60%, dan 85% sebagai representasi tingkat keparahan penyempitan. Model matematika disusun berdasarkan persamaan konservasi massa, momentum, dan energi untuk aliran tak termampatkan, kemudian dimodifikasi menggunakan viskositas efektif Casson yang bergantung pada laju regangan geser. Persamaan model dinondimensionalisasi, didiskritisasi menggunakan Metode Volume Hingga dengan skema upwind orde pertama, dan diselesaikan menggunakan algoritma SIMPLE. Penyelesaian numerik diimplementasikan menggunakan MATLAB dan ANSYS untuk memperoleh kontur serta profil distribusi kecepatan, tekanan, dan temperatur pada setiap variasi stenosis. Hasil penelitian menunjukkan bahwa peningkatan ketebalan stenosis mempersempit luas penampang efektif sehingga meningkatkan kecepatan lokal pada daerah throat, menaikkan tekanan ukur pada daerah upstream, serta memperbesar laju regangan geser. Konfigurasi Cosine–Bell dengan ketebalan 85% menghasilkan kondisi paling kritis, dengan kecepatan maksimum 198,20 mm/s, tekanan upstream 8,229–8,437 mmHg, perubahan temperatur maksimum 268,20 µK, dan laju regangan geser sekitar 1622,32 s⁻¹. Pendekatan Casson menunjukkan adanya penurunan viskositas efektif pada daerah shear tinggi, sehingga mampu menjelaskan respons reologi darah secara lokal akibat stenosis.
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Central Retinal Vein Occlusion (CRVO) is a retinal vascular disorder that can obstruct venous drainage, increase flow resistance, alter local pressure distribution, promote retinal edema, and impair visual function. This study investigates CRVO hemodynamics through numerical simulation of blood flow in a retinal vein with asymmetric stenosis, considering blood as a non-Newtonian Casson fluid. The stenosis geometry is constructed from combinations of Overlapping, Cosine, and Bell profiles, namely Overlapping–Bell, Overlapping–Cosine, and Cosine–Bell, with thickness variations of 35%, 60%, and 85% representing different severities of narrowing. The mathematical model is formulated from the conservation equations of mass, momentum, and energy for incompressible flow, and is modified using the Casson effective viscosity, which depends on the local shear rate. The governing equations are nondimensionalized, discretized using the Finite Volume Method with a first-order upwind scheme, and solved using the SIMPLE algorithm. The numerical solution is implemented using MATLAB and ANSYS to obtain contours and profiles of velocity, pressure, and temperature distributions for each stenosis variation. The results show that increasing stenosis thickness reduces the effective flow area, thereby increasing the local velocity at the throat, raising the gauge pressure in the upstream region, and intensifying the shear rate. The Cosine–Bell configuration with 85% stenosis produces the most critical condition, with a maximum velocity of 198.20 mm/s, upstream pressure of 8.229–8.437 mmHg, maximum temperature change of 268.20 µK, and shear rate of approximately 1622.32 s⁻¹. The Casson approach also shows a decrease in effective viscosity in high-shear regions, providing a clearer description of the local rheological response of blood under stenotic conditions.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Central Retinal Vein Occlusion,Fluida Casson, Metode Volume Hingga, Algoritma SIMPLE ============================================================ Central Retinal Vein Occlusion, Casson Fluid, Finite Volume Method, SIMPLE Algorithm
Subjects:	R Medicine > RE Ophthalmology > RE48 Eye--Diseases. Ophthalmoscopy. T Technology > TA Engineering (General). Civil engineering (General) > TA357 Computational fluid dynamics. Fluid Mechanics
Divisions:	Faculty of Mathematics and Science > Mathematics
Depositing User:	Juan Randy Christian Putra
Date Deposited:	27 Jul 2026 02:27
Last Modified:	27 Jul 2026 02:27
URI:	http://repository.its.ac.id/id/eprint/137677

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