Hrvatske vode
 
Numeričko modeliranje morfodinamike poprečnog profila na šljunčanom žalu Medveja
Numerical modelling of morphodynamics of the Medveja pebble beach cross section

Goran Lončar1, Damir Bekić1, Dalibor Carević1, Hrvoje Mostečak1, Maria Babić1, Nina Grbić1, Vjera Pranjić1

Sažetak/Abstract: 

Provedena je numerička analiza morfodinamike karakterističnog poprečnog profila šljunčanog žala Medveja. Osnovna pobuda na pokretanje šljunka u profilu žalo/podmorje su gravitacioni vjetrovni valovi, dok strujanje mora inducirano plimotvornom silom, gradijentnim strujama i strujama drifta nije uzeto u obzir. Prvotno je uspostavljen numerički model valnog generiranja i valnih deformacija za akvatorij koji obuhvaća Kvarner i Riječki zaljev te je njime proračunata prostorna i vremenska raspodjela značajnih valnih visina HS i vršnih valnih perioda TP tijekom 2013. godine. Modelski rezultati HS i TP za dubokovodnu točku ispred ulaza u uvalu Medveja definiraju rubne uvjete detaljnog modela valnih deformacija i morfodinamike u prelaznom i plitkovodnom području za karakteristični profil žalo/podmorje u uvali Medveja. U nastavku je analizirano ponašanje hipotetskog profila dobivenog nasipavanjem na stvarni (snimljeni) profil s ciljem povećanja kupališnog prostora. Rezultati modelskih analiza ukazuju na zone izražene erozije i sedimentacije uzduž analiziranog profila te težnje za uspostavom ravnotežnog profila koji koincidira sa stvarnim-izmjerenim. Modelom proračunati profil uspoređen je s izračunatim temeljem empirijskog izraza. Rezultati numeričkog morfodinamičkog modela potvrđuju mogućnost njegove primjene u svrhu procjene intenziteta destruktivnog djelovanje jakih valova na lice šljunčanih žala.

 

A numerical analysis was conducted to determine the morphodynamics of the Medveja pebble beach characteristic cross section. Pebbled movement in the beach / seabed profile is primarily induced by gravity wind waves, whereas marine currents caused by tidal force, current gradients and drift currents were not taken into account. A numerical model of wave generation and wave deformation was initally established for the waters of Kvarner and Rijeka Bays to calculate the spatial and temporal distribution of significant wave heights HS and peak wave periods TP in 2013. The model results HS and TP for the deep water point in front of the Meveja cove define the boundary conditions of a detailed model of wave deformation and morphodynamics in the transitional and shallow water area for the characteristic Medveja Cove pebble beach / seabed profile. The paper contains an analysis of a hypothetical profile obtained by backfilling on the actual (recorded) profile to achieve increased bathing area. The results of model analyses indicate zones with marked erosion and sedimentation along the analysed profile and a tendency of establishing the equilibrium profile which coincides with the actual measured profile. The modelcalculated profile was compared with the empirically calculated profile. The results of the numerical morphodynamic model confirm the possibility of its application to assessment of the intensity of destructive activity of strong waves on pebble beaches.

Kategorija: 
Prethodno priopćenje / Preliminary Report
Ključne riječi/Key words: 

šljunčano žalo, numerički model XBeach-G, morfodinamika

pebble beach, numerical model XBeach-G, morphodynamics

Podaci o autorima/Authors affiliations: 

1Sveučilište u Zagrebu, Građevinski fakultet, Zavod za hidrotehniku, Kačićeva 26, 10000 Zagreb, Hrvatska, goran.loncar@grad.unizg.hr

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